Yes the V5 AND the V5.5 are both great, but they both have pros (good) and cons (bad).
V5 Pros: Very good fact of raising a family is great. TONS of new characters. Can connect with the Music Star and V5.5 Celebrity. Tama&Earth Expo is fun and very interactive. The game itself is interactive. They make a "Beep" when they poop. 5 hearts instead of 4. Bonding. Family name (for some people). Nice games. Tons of codes and cheats, and the "Pure Families". And finally, pets that have pets.
V5 Cons: Family name instead of name (for some people). No names, age (but you can track it), skill points, and weight. Very different from the older Tamagotchis (for some people). Not that ordinary. Only 2 games that you'll get tired of until the 2nd Generation. The middle tamagotchi (oldest) hogs ALL of the attention.
V5.5 "Celebrity" pros: Still keeps the Family feature. Tons of new characters. Introduces Gotchi King, Gotchi Quenn, Princess Tamako, and Princess Tamakoko as characters you can get. You can now go to the Celebrity Cruise Ship. Bonding, Family name (for some people). Codes depending on characters (for some people)
V5.5 cons: The point where they start turning into divas/popstars (not comparing to the V6 "Music Star"). No pets in the "Pure Families". Too many new characters (for some people). Not very original. No names, age, skill points, and weight. Characters might look a bit weird to you (because they are new). Codes depend
Just a Pros and Cons view. Hope I helped!
:furawatchi: