Updates for the 2010 Acura MDX crossover bring a new corporate grille, revised front and rear fascias, an updated V6 engine paired with a new six-speed transmission, a freshened cabin and a gaggle of new high-tech goodies. The latter include a hard-drive-based navigation system (with music storage, traffic rerouting and weather reporting) and a multi-angle back-up camera.
the most obvious differences are the looks of the car (ie the grill and the exhaust tips). 5 spd vs 6 spd tranny. SHAWD system is the same.
you have to decide which look you prefer or if the subtle differences with the tech goodies (assuming you go with the tech pkg) are preferred. then you have to decide what you are most comfortable paying and the mileage on the vehicle. lots of factors. looks are purely subjective. 08-09 vs the 10...more or less the same car with the exception of the trannies.
IMO After driving a loaner 2012, that transmission feels the same to me. Although if for some reason you want to sport shift, maybe a 6 speed could be more fun. Acura claims that it helps MPG by 1 on the highway I think. And someone correct me if I'm wrong, but I believe the '10s and up steering is softer. I know for sure my '08 is stiff compared to the 2012 I drove.
your best determinant...test drive one of each and see if you can tell a difference.
1 mpg difference is not really that significant. not sure about the steering.
for me the looks were the biggest factor when choosing. the new "plenum" grill has grown on me...i'm not in love with it (this is purely subjective). if the looks don't matter to you...then you have the other "little" things to compare and decide. also consider what you are most comfortable owning.