Weak.
The only thing decent about this game is the very detailed practice mode with many variables to play with. This helps you learn your fighting moves and hone your technique. The issue is that the ghosts are not all that fun to play against and online is too spotty. You can have a good fight or two, but you will find a number of your fights will have intermittent lag. So if you don't have a friend to play with at your house I'm not sure what you will do with all that training.
All around I am very glad I rented this instead of buying. Please don't encourage another version of the weak crap by purchasing. Just pass. Maybe Tekken needs to die off and resurface in a few years with a new team - and maybe some original or at least fun gameplay. If you have any previous version of Tekken just keep playing that.