Well, I have had two sets of the BFGs on my 4Runner and like them. I have gotten good mileage on them. They are quiet until the last 6 to 8 thousand miles, then they make a little noise (not bad at all - the Trac is far better insolated for noise than the 4Runner). They handle well on or off road.
I have not used the ProComps.
From the tread designs, the BFG is a bit more aggressive. From what I see, there are a lot more BFG A/Ts out there than ProComp A/Ts. It may get down to what you want them to do for you.
Hope this helps.