one thing to look out for when buying through AAFES, the salesman will tell you 'tax-free', but that isn't really true. it is more like 'tax-deferred'. when you bring your ride back to the states, and go to register it at the local dmv, if you can't show that you paid sales tax on it, they will hit you up for that before they give you your plate. if the vehicle is less than 2 years old, they will hit you up for full tax (at least here in la). over 2 years, you'll pay tax on what they determin book value to be.
this may be common knowledge to many here, but i saw a couple of soldiers that got put in a serious hardship because of this when i was deployed to iraq.
as far as AAFES pricing, the only 'deal' that i saw when deployed was that for the same price that i would pay at my 'local' dealer, AAFES included an additional 1 year extended warranty.