Well, don't sell the Academy submissions short. For the price of the Tamiya kit, you can get the Academy one AND a really nice aftermarket set-up! Or you could go with the Trumpeter ones (which are just Academy knockoffs IMO) and do the same thing with the aftermarket stuff for even LESS money.
I have built one Tamiya Hummer and many Academy and Trumpeter kits and I must say there is really no difference in the build. All of them go together quickly. However, when you get the Academy or the Trumpeter ones you feel less restrained in kitbashing or modifying because you have less money invested.