The versions that I do not like are v2, v3, v4 and v4.5.
One thing that I don't like about all the above versions is that you need to complete a game perfectly to lose 3g of weight. I suppose on the v2 it isn't that bad because Jump is very short.
On v3, there were a ton of glitches and it still had the same you-must-complete-the-game-to-lose-3g-of-weight rule. It also had an annoying antenna.
On v4, it still had that annoying rule as well as extremely annoying games and jobs. There was also a super annoying antenna. The games are just too long in my opinion. I timed myself playing the regular games and this is approximately how long it took:
Jumping Rope- 1min 50sec
Mimic- 3min
Shape- 1min 30sec
Dance- 2min 30sec
Flag- 1min 40sec
I'm assuming that v4.5 was the same. I have played a few games on the v4.5, but the most I've done on a v4.5 was feed it a few meals and play a few games so I haven't truly experienced it.
One annoying thing on the v4 (and perhaps v4.5 but I'm not sure) is that the Matchmaker only stayed on screen for 10 seconds, making her very easy to miss! Usually I caught the Matchmaker by setting the itme to 10.29am, 2.59pm or 6.59pm and waiting a minute.
Here are all of the Tamagotchi Connexion versions in the order I like them:
1. v1 tied with v5
2. v2
3. v3, v4 and v4.5 tied- but I dislike v4 a bit more than the other two.