v1: Loved this version. The games didn't take up much of my time at all, especially since I didn't have to play the game the whole way through to lose the maximum amount of weight for that game (one thing that really annoyed me about future versions). It felt like I was caring for my little Tamagotchi that depended on me to thrive and since there were only a handful of characters compared to future releases, I got to know them all well and I liked them all, though I got a bit fed up of Mametchi/Mimitchi because I got so many of them.
v2: I don't have one of these but I did look after my friend's for a couple of days once. I didn't mind Jump, because that was a quick game which didn't take up much of my time. It did feel like other people were continuously fattening up their Tamagotchi to play Bump and it was like a competition at my school to see whose Tamagotchi could go through the most rounds of Bump! People seemed to care less about caring for their Tamagotchi and more about playing the games and getting lots of Gotchi Points. (Then again, they never did care about caring for their Tamagotchi. They cared far more about connecting, connecting and connecting. People then started to believe that that was all that a Tamagotchi was about.)
v3: I didn't like this version because of the long, irritating games. I liked a few of the characters I got on this Tamagotchi, most of all Bunbutchi/Bunbuntchi, but other than that I didn't like this Tamagotchi very much. The antenna annoyed me, too. This version seemed more about the games and Tamatown than the caring-for-your-Tamagotchi concept.
v4: And I thought v3 was bad! I want my Tamagotchi as a Tamagotchi again! I don't want all these annoying games and other features (such as mail, jobs etc.) that I feel take up too much of my time.
v4.5: I don't have this version (didn't like v4) but I have played on my friend's v4.5. I thought the games were better on this version but that was the only good thing I thought about it.
v5: I liked this version more than any other Tamagotchi (not counting originals because I haven't played with one) besides v1. However, I did find it pretty boring, unless I was raising another Tamagotchi at the same time. Another thing is that this Tamagotchi didn't really make me feel motivated to care for my Tamagotchi. This might have been because, unlike v1, there was no discipline or any reason to make your Tamagotchi exercise on this version.
As for v5.5 and Music Star... haven't played with either.