Used both the M60 and the M60E3 in the Corps and was a SAW gunner (M249) for a time.
I liked the M60 over the E3 even though it was heavier. The E3 had problems with the bolts wearing down too quickly.
The SAW was great. We had one on each STA Team in 2/8 and 2/6. For a three-man team...