I would say don't let the language barrier ward you off, there a tons of online guides and resources to help you work your way through the menus and do your research. I would then refer you to Ra Tamazone on youtube as he has some fantastic reviews of the colour tamagotchis and quite a few of the connections (and for whatever connections he does not do there are others out there).
I cannot say which model is the end all and be all that will fit the bill of what you want.
The Connections are much smaller than the colours, so if you are looking for something small and compact, then they are what you are looking for. The tamagotchi connection V1 is the vanilla model. It can connect to other connections, marry between them and there is a match maker that comes but that's it. It has simpler growth chart.
The V2 is my personal favourite this was the connection that introduced the shop and gotchi points. You win gotchi points by playing games (which are unlocked throughout growth) and you can go to the shop that has 1 items and it restocks at set times and you can purchase treats or toys for your tamagotchi to play with. This model has some model exclusive characters and if you ask me it has the best selection.
The V3 has the small antenna a design choice that I still call silly. This Tamagotchi is very similar to the V2, there are different games and instead of one meal and one snack option there are sets of 4 built in options to choose from. Treats purchased from the store are now divided into meals and snacks (which isn't an upgrade on the treat system). The games are easier but items are also a tad more pricey. There are a lot of characters that are present on older models (going back to the vintages and the previous 2 connection models)
The V4 introduces the Guts system and is the watered down version of the Japanese Entama, This one usually features the antenna with a ball. The Guts system is a way to dictate growth on the tamagotchi after the teen stage. There are 4 different tamagotchi families (these are at random) and within the family and gender the category with the most points will dictate the adult character. The games add to Guts points as well as give gotchi points. The light switch has been replaced by a mail box that will beep and flash randomly throughout the day (really not a fan of that). Discipline is no longer used for growth determination. As well there is school to help your tamagotchi gain guts points as well as afterwards a job interview and after some time of having the job you will have to find another one. Each job has a mini game that you must play in order ot get your pay check the next day.
The V4.5 is very similar to the V4 only different characters, jobs and guts points.
The V5 of the famitama is rather unique you raise from 1-3 tamagotchis at once and the bonding level dictates growth. There is no weight meter. Functionally you feed one, and clean the poop as normal but you have multiple sprites on screen. This tamagotchi I find is very low maintence and there is no age counter so no rush for the match maker as there are no oldies (which people hate but I don't see why). The match maker this time around is a tv program that once your tamagotchis are old enough you can go to. But really cute animations
The royal famitama of V5.5 is very similar to the V5 only different characters and games and animations
The V6 is the music star and is also a dear favourite but also very high maitence you are raising a music star who practices music or plays (to decrease stress) all throughout the day. And you have to maintain low stress levels music skill points deal with no way to make cash until you make it big (or get low paying jobs) and band practice. There is a lot going on so its really an all in tamagotchi.
There is the tamagotchi Go It's much bigger than the connections it features the figures that add games and such (as far as I know I don't have one) I know you can potty train the tamagotchi which is nice.
The Friends and Dream town - I recommend the dream town it is the better version they are similar. The dream town introduces dream school -- where you can play games to give your tamagotchi a personality and that will help direct evolution. These tamagotchis are built to be neglected and not to punish you all that much. Most of the chracters are featured on the colour tamagotchis. You collect jewlery by evolution and buying it.
All of these come in english if that's your concern and I would suggest they are all suitable for testing out of hey do I still like this now if we can look past the language (don't worry they aren't made to be crazy complicated at all)
Plus colour - first colour version and the most simple. Strictly in Japanese, There are no downloads for this tamagotchi. It's a very complete tamagotchi with seasonal animations, daily weather, location unlocks, and the ability to grow oldies and special characters (from oldies). There are some wallpapers to play around with lucky symbols to collect and two games. This one is really cute. Also there is a really good guide on this one here on tamatalk
The ID - this one does come with downloads and introduces the tamatomo stamps that are different for every adult character and collection the all the stamps in the notebook (adds the idea of goals or progress). This one has more places to eat food, and donuts - daily donut flavour. 2 built in games (1 or 2 more by downloads) again wallpapers. There is a photostudio which you can dress up your tamagotchi for a picture which is really cute. Again this one is only in english. But again its not really reliant on language. And there are lots of guides
The IDL - this one includes more characters that you can raise 4 secret adults tons of downloads. Tamatomo is replaced by happy symbols. As you collect tamatomos in the notebook locations are unlocked including one that for some characters dresses them up into their alteregos. There are 3 versions the IDL, IDL princess Spacy and IDL 15th anniversary. There dont differ all that much mostly characters, food items, wallpapers, and games. The mechanics are all the same. This is my favourite colour version. This one comes in english but the english version is very pricy (and I would say really not worth it). There are trees to plant, pets to adopt at the park and so on. Again there are lots of guides
The Ps -- there is an all english patch available so technically it can be in english the prices on these bad boys are insane for the most part. Similar to the IDL. Add personality points to alter growth aside from care misses, remove planting trees, reduces the number of pets to adopt. Adds part time jobs school and daycare. All three drop the meters and once they are empty (or the time is up) then your tama is sent home starving and angry. VDPs add the number of characters you can raise and the VDP+s are reducing the need to buy the physical pierces. This is a community favourite so you bet there are guides
4u/4u+ - this was has skills such as potty training which i think returns us to the pet feel of the tamaogotchi there are school points also. There are post adult evolutions which increase the raisable adults but without the app there are limited adults. These tamas connect via NFC. I love the daycare in this one though as the meters are frozen for however long you are at daycare for. The 4u does have an english patch but not the 4u+. I enjoy it but not for the longterm. The guides are less in depth or thorough as this one didn't get a lot of love
MIx -- all versions as they are all crazy similar -- they are all in Japanese and they are the newest model. They introduce the idea of genetics and mixing of adults to generate new characters. there are 4 traits given to each adult and as your baby grows they will grow these traits slowly until they are adults (which is cute). There are random animations such as trick or treaters snowball fights and so on some people don't like this but I do. There are various locations you can travel to to shop, visit a location specific venue or meet and play with tamagotchis. And you have to increase your frienship levels with one of the opposite sex to marry (orange you can propose and hope they say yes or cheap out and keep showing up until they propose). There are food items that change the colour of your tama that is inheritable by the next generation. This one a bit simpler than others as there are no tamatomos (so some feel no goal) but the goal is to mix as much as you can and generate as many unique tamagotchis as possible and no matter how many times I run my mix I have yet to have two of the exact same adults they differ by either a lot or subtle differences. The difference versions differ in the locations and the built in adults you can mix with. All english I can't say if that will remain or if Mister blinky with develop a patch
And that is a short summary of the different models from connection to colour era so that you can make an educated decision on which model is best for you and so on. Price wise the connections and friends/ dream town will generally cost less than the Colours. And the newness of the mixes may make them cheaper but I haven't been shopping around so I could be wrong
