Totally different from Tekken 5: Dark Resurrection.
The thing is that in T6, the characters are sort of cartoonized (same as in prince of persia the last game) which makes the graphics look a bit ridiculous.
Though apart from that there are new customizations which are very different from T5. The new hair system, and the aura apart from the extra items are really cool.
In T6, the most stupid thing i found is that in both arcade and ghost battles.. you are shown the rank of the character you're using and his/her fighting battles (Wins, Losses, Draws and percentage).. which is a bit tedious since in the previous Tekken, one could just do arcade battle for fun without having to worry about the ranks.
In the story mode, i found out that the character fighting length is short, you get to fight two characters, jin and Azazel. Thing about Azazel (the boss monster) is really annoying because if you're trying good hits, they don't work on him (he has a special block and can attack you while you're attacking him)... and if you attack him, he can counter you back dealing quite a good amount of damage and sends you flying for a massive combo of his.
The characters have improved moves and also the new feature of bouncing adds up to the special effects of the new T6 which makes it unique so far. The new characters are quite a handful because all 5 of them posses strength and agility which makes them quite challenging to beat. The ending movies are somewhat hilarious (Bob, ganryu, lei wulong ect) but there are other sad movies and interesting ones as well.
Above all, this game is good and if you want to try and master the newly and improved characters, go ahead but i recommend you look at the trailers and check some reviews first.