The A2 stock I used in Basic was just fine, the cool M4 stock on my M4A1 was super tacticool when I got to play with it. Than they threw in rails, VFG, lights and lasers.
I've used them all: A1, A2, CAR, M4, SOPMOD, VLTOR, 93B, CTR, ACE SOCOM, ARFX and more I don't remember.
The best has been the SOPMOD handsdown, it is beaten in terms of features by all the Magpul stock, it wins because of the cheekweld. I do not own one however as I want to be cool more than having an effective cheekweld. I will buy the UBR when it hits because I am a Magpul whore and I want my rifle to be as Gucci as possible. All the Larue stuff on my MRP upper begs to be paired up with something like a UBR. I hope that Magpul will actually offer the side saddle options to improve cheekweld as they promised on the M93B but never delivered. If the UBR can get the awesome cheekweld of the SOPMOD I will be able to tell people that I bought it for the function and not just because I'm a gear whore.
If Dolce & Gabbana made slings I would be there.