I can't believe this forum is so biased
Go the 6. If you have enough money go for the TSX with NAV system and all the bells and whistles.
Also note that the 6 has a 6-speed auto this year for the V6.
Anyways there are 3 reasons I think the 6 is better than the TSX; of course maybe they are preferences.
1. the door locks; the TSX has the traditional door locks sticking out by the windows; the 6 has them inside and gives the window a smooth look; guess this much more aesthetics more than anything
2. the centre dash container; this is so convienient as the way it opens you can see what stuff you put it there and its much easier to take stuff out.
3. the hatch (which also gives you a rear wiper) has so much space; i think you can put two bikes in there without taking off the front wheels.
To me, the TSX and 6 are virtually identical; the cupholders, audio/cruise control are virtually identically and in the same place. They are approximately the same size and have the same large turning radius (6 is abit smaller); I am thinking someone must have copied the other when building these two great cars.
But then again if you care for reputation and service go with the Acura because its LUXURY. Mazda reputation and service isnt as well known.