I was looking forward to the release of Tekken 6 for months, unfortunately I've been nothing but disappointed from the moment my copy arrived. First disappointment came from reading the box - the game is 720p. How in the world did Namco decide to downgrade the graphics after giving us Tekken 5: Dark Resurrection which ran at silky smooth rates @ 1080p? Unfortunately, the resolution downgrade, is not the only issue. Soul Calibur 4 runs at 720p and has great graphics and audio, Tekken 6 does not. The textures and the backgrounds are poor and are highly compressed - you won't have to pixel peep to see this. Same goes for the sound effects and music. Tekken 6's audio, both music and effects, comes out muffled due to, probably, high compression.
On its own, Tekken 6 is not a horrible game - it's an OK game, but when compared to the previous entry in the series it's one big disappointment. Namco has failed here. They gave us an amazing 1080p game in 2007, with amazing sound track/effects - truly arcade quality production values, only to come back two years later with a game that's worse in every aspect. Bottom line, you should only get this game if you are a diehard Tekken fan and absolutely must have everything that's Tekken related.
Otherwise, if you already have a game in this genre and are on a budget - skip this one.