We had the AUG for a while. I was glad to dump it for the M4.
About 4 years back, We got 4 full auto SBR SCARs sent to the office. we were supposed to let the SRT (swat) types and instructors finger them for 30 days. We took a survey on what we thought, and took a vote. Dump the M4 for the new sexy SCAR, or keep the M4? It was unanimous to keep the M4.
Funny thing is, on day one, it was close to unanimous to switch to the SCAR when everyone was fingering them in the office. "It looks sooooo cool". Then they spent a few days running with them and shooting them. The "looks cool" gave way to "this kind of sucks" pretty quickly.
Do we have some issues with our M4s? Yes. Typically its people trying to armorer shit they don't know how to armor. Last week I had a 3 round burst cam screw the gun, so that in semi, they gun had a dead trigger (fail to reset) every three rounds. But over all, they run well.