I am currently in Iraq and I carry an M4. I can't complain...it is light and handy, easy to maintain, and I have not had any serious malfunctions. Ideally, though, I think the longer M16A2 chambered for 308 would be nicer. But I guess that would not have any advantage over the M14...so my final answer is M14, but my M4 is doing well for me here.