People may not say it's a decent fighter, I don't really know for sure about others' opinions, I must recommend DBZ: Budokai Tenkaichi 3. However, I will recommend that you also stay far far away from Wi-Fi battling unless you have something along the lines of a T1 connection or something because you have anything less and you'll lag so horribly.
But with a solid combat system that appears to take combo-based fighting systems to a somewhat new level, tag-team matches with up to four other teammates in your team, a solid story mode covering every arc in the Dragon Ball Universe including the original Dragonball, Dragon Ball Z, Dragon Ball GT, all of the movies, the Bardock OVA, A cameo scenario from Dr. Slump, a series of What-if scenarios, five or six different survival modes, several (100+) event-based fights, a unique kind of Arcade Mode that operates with more of an RPG twist to it, five different kinds of tournament modes, all of which with its own rules, 150 or so different characters (only about 100-ish already available, with the rest needing to be unlocked), etc.
There are some downsides such as Giant characters that are much more difficult to beat, yet they themselves are much slower, so they're hard to fight with and hard to fight against. Another downside, as I mentioned before, was Wi-Fi. In comparison to a LOT of other Wi-Fi titles, this game fails at life.
With all of that said, I say that you should get this game, just don't take it online.