Bushmaster makes good AR's. don't listen to some of the brand snobs.
Sure there are better manufacturers out there, but there are also worse ones. I would put Bushmaster in a mid-tier category IMO. It is very reliable and servicable in my experience.
My very first AR15 was a Bushmaster M4A3 Carbine. Excellent quality and reliability. My only regret was selling it a few years back when money was tight. I would buy another one in a heartbeat. For $750 locally, buy 2 !!