It really depends who you are.
If you have a lot of time on your hands and aren't like studying for an exam or job or anything, then go for the V6. It's really great for people who have a lot of time. If you don't have a lot of free time, don't run it, since Music Skill Points DO affect your character and you might end up with something really awful of you don't have enough time to get Skill Points.
If you're a busy person who has school or work or anything, then the V4 is great. It's simple, and all you really have to do is play the short games and feed it. It doesn't matter if you neglect it, none of the characters are too bad, although not as cute as some of the Perfect Care ones on the V6. It doesn't die easily. I used to kill V6s on purpose (when I was 8! I'm almost 10 and a half now!) and my record for the shortest time it took was three hours twelve minutes. That was just neglecting it all through the baby stage and into the toddler stage, not deliberately feeding it a million snacks, just turning the sound off and ignoring it, so I doubt it would get on at all well at school.
I voted for the V4, because overall I think there are more characters, and I love the school/job feature, and the skill points, but you're not under pressure to bother about skill points since all the charactaers are pretty cute. It's really low-maintenance, the ideal Tama if you're gonna be going out and going to school all the time.
~ Dazzmina ~
And I've read reviews and things about the Music Star and I have a sudden urge to try it out. Should I? 
