I just got a few parts through my SOT from Bushmaster and I was pretty impressed. Everything was a great looking phosphate finish.
All together I replaced the buffer and buffer spring, autosear, hammer, hammer and trigger pins, selector and the bolt carrier.
Once everything was installed, including a new M16 carrier, the timing was still dead on.
The trigger pull was actuall BETTER after I put in the new parts.
Once the gas rings seated and some of the finish wore off of the autosear and it's notch on the hammer the cyclic rate settled down to around 750rpm with M193 ball using my 20" upper.
Normally you don't buy M16 parts with the expectation of an improved trigger pull but I found that to be the case.
I compared these parts to a set from Bushmaster's smaller competitors and there was an obvious difference in the autosears and the selectors. Bushmaster's was cleanly machined and better finished. Brand X's had a thin gray phosphate finish.
For those of you about to do any work on a registered lower or setting up a RDIAS you should consider getting Bushmaster parts. Other vendors may sell parts from the same sources and for a little less, but at least you KNOW what you're getting with Bushmaster.
Unlike Colt, you can actually buy M16 parts from Bushmaster as a mere mortal with a Form 4.