Red Dot MOA???

I have no experience with the Burris fast fire.. But here's some observations with the optics I have with different reticules.

Aimpoint T-1 (4moa) -- very effective at 75yds and under. Large enough to be seen rather quickly when brought to bear. Great for carbine classes and competition with targets under 75yds. At 100 yds outdoors, at the "8" setting, it's bright enough to sight in on a white target and still avoid bloom of the reticule. At 100 and above though, the dot becomes fairly obstructive and covers most target boxes that are 4-6 inches diameter.

Aimpoint T-1 (2moa) -- very similar. I don't actually notice much of a difference under 75yds. The only time I notice is on a non contrasting background (large white area). It does make it easier to aim at targets outside the 75yd range. Im able to pull off 2-3moa at Calverton 100yd with grip pod. At the 200yd it covers up a decent chunk of the target.

EOTech EXPS3-0/EOTech 552 (1 MOA center dot, 65moa ring) -- by far my favorite reticule. Makes snap shots up to 100yd VERY quick. I was able to pull off 1-2 MOA with the SCAR at 100 with consistency. 1 MOA dot works well beyond 100. Great reticule at the cost of a heavier optic and less batt life.

Trijicon RMR (8moa) -- I had this optic for a while when i was considering a FN pistol. I tried mounting it on a riser and used it with an AR. Pretty effective at 25 yds. Makes target acquisition fast at Mitchell field distance. Pretty difficult at 50-100yds. I had some trouble sighting it in because the dot was larger than the target. Better left to pistols or CQB backup sights.

You didn't mention what kind of gun it's to be mounted on. If its a carbine I'd stick with the smallest MOA you can get. You will eventually get consistent with bringing it to bear and that dot isn't hard to find. If its a pistol or some kind of pistol caliber carbine. You can definately go bigger and shave some milliseconds off sighting in your target