The RMR 02 was the first of my now many RMRs. I have grown to appreciate the always on, no brightness adjustment function. One problem Ive encountered with the adjustable models is they can turn off during use or change brightness from recoil or gun handling (the cheaper Burris fast fires are worse for this) The RMR 02 was my first Trijicon pistol red dot and I retired it and bought an RMR07 after I tried the RMR 02 and did not like the way too bright dot that was not adjustable. I also did not appreciate the lack of an on/off switch. Now after having more time training with pistol red dots I can see the RMR 02s value for competition or conceal carry. No on/off switch or brightness adjustment means it is not likely to auto/accidental adjust or turn off when needed. The overly bright (and hallowed) dot mellows as the battery ages a bit and I know that this thing will perform without fuss when needed. Now the RMR 02 (non-adjustable) and the RMR 04 (battery free) are my preferred units.
Pros: won't be off or too dim when needed, small and lite, clear
Cons: battery replacement requires removal, dot a bit too bright
This review was written in the old system and had content requirements that are different than reviews written today.