They are not the same, there are many differences. Ps- the Music star is not the V6.
There are to many differences to post, but they both have different concepts. On the v5.5 your supposed to raise celebrities. it is more family based. The beeps and screen is different, along with food and game. The whole tama is different. On the Music Star, your on a quest to raise a musical star. Also new games and foods. It's shaped like a v1 and a v2... There are many differences and you should do your research. tama.zone is a good place to start
Good luck- Haru