Jason
I never used the Doctor sight, though I hear they have a good reputation. I do have several Fastfires; one on an AR, and one on a 1911 .45acp. In both applications, I think they work well, and have proven durable, as well as maintained there sight in settings. A bonus is the small size. One thing I have noticed is battery draw, in the "sleep mode" (unit turned on, with cover in place) will still draw a battery down to quick for my taste. I always turn the unit off when I am done using it, and have had excellent battery life that way. Leupold makes a similar sight, as does J-Point, but both are more $. We had real Eotech's on are issue M-4 and Colt 9mm sub guns at work. They have excellent battery life, and are all around great sights, but are bulky, and expensive.
Larry