servo's
just my experience
I have only ran a few brands of servos(jr, ace, airtronics and hitec. The ace servos were fast and smooth, worked well for the money but just did not last. I was replacing gears constantly and the top case cover around the brass bushing. I had good luck with some of the JR servo's. The DS 8711 was bullet proof for me, I ran it in 2 truggy's and a buggy and was still working when I took it out. I only had 1 problem with the 9100T, but the 9100s's were a constant problem. Same problem as the ACE, gears or top case cover. Jr's service treated me well it's just a hassle and a big bummer when your 3 hrs from home racing and it fails.
Airtronics servos seemed to be smooth and fast but honestly I didn't give them much of a chance before installing Hitec 7955's in all my rigs. I been running the 7955's and controlling them with the M11X. It has been almost a year now and I have not had 1 single problem. The 7955 is smooth, fast, strong and thus far very reliable. Although I have not had to use Hitec's service I hear it's great.
Hitec took my vote.