Tatsunnoko vs capcom is a great fighting game, which isn't let down by the wii hardware at all!as one of the reviews below suggest (infact the original arcade game was built on wii hardware so theirs no frame dips etc in the conversion to the console)
The cast of fighters is very good to which is great because when online your not just playing against ryu and ken like on street fighter 4.
As for online i have no problems with lag when playing 90% of the time.You can also choose to find people in the same country or worldwide, as for finding a game it normally take about 1-2mins which is a bit of a pain, but thankfully you can rematch the same player again and again and add to your rival roaster if you both agree to it.
graphics are clean and crisp running via component(480p)
Sound is pretty good although i preferred the Japanese version of tatsunoko vs capcom cross generation of heroes where the music would change when a new fighter would enter the fight.
All in all i defo recommend tatsunoko vs capcom to everyone!
its different enough to street fighter4 to warrant a purchase if you already have sf4