I really think that would come down to personal preference. If you want to get really into it, you could look at lapping the mating surface on the upper to be truly square to the barrel extension, and if you have slop between the upper and extension, you could shim it or bed it. Other than those things, I don't think there's very much going on with the upper receiver or free float tube that really affect function or accuracy.
The fancy machined billet stuff may look better to some folks, but I really think it's mostly cosmetic. Of course, I could be totally wrong.
My taste leans toward a forged upper minus the forward assist. Aero makes one with the dust cover and brass deflector, but no forward assist. I really like that look, and I've never needed the forward assist in all my years of shooting either in the military or out. It's a cleaner look with a minor weight savings too.
Find the parts you like to look at, and go with them.