Hmm..I like the V5. It's..well, easy. Hehe. Granted, I've only had it for like..two days, but still. As an adult person without a lot of time, I value the fact that it's easy. Hehe. I appreciate that I don't have to constantly monitor the thing in order to keep it alive, let alone get "good" characters. Which is good!
The other versions, which I have, are all lots of fun but sometimes it feels a little bit too complicated when I'm trying to do other things..not to mention the constant feeding and play the others seem to require. Hehe.
So, bottom line, I'd say that the V5 is a more laid back experience. If you want more of a challenge, more stimulation, go with an earlier version.