I am getting ready to buy either an Trijicon reflex or an Eoctech 553 for my PS90. Now I probably don't know as much about these as some of you so what are the pros and cons to these or what else is on the market that is comparable. I have an ACOG on my FS2000 and have been very happy with it! I tend to be VERY brand faithful but would give serious consideration to any quality product out there.
Don't forget Murphy's law.
Most holigraphic and red dot sights I've encountered rely solely on batteries and electronics to illuminate the sight and make it useable. And I have yet to encounter a battery operated device that I did not try to use at some point only to find the batteries dead. Even devices like sights that I always tried to keep the batteries fresh in and had ridiculously long battery life to begin with.
Most reflex sights I've encountered rely largely on ambient light to illuminate the sight and make it useable. The good ones also use Tritium thats great for dim light. But there are still ambient lighting conditions that these sights are useless in. No better than a holographic sight or red dot sight with a dead battery.
So the lesson is, get an optical sight with an etched reticle if you can. Then the sight is useable even if its illumination system is failing you. Get an optical sight with an electrical
and a non electrical illumination system if you can. Best of all, get a sight that offers both of these if you can. And of course in a pinch there is always backup iron sights its noce to have.
Some of my favorites that I don't hesitate to use for serious purposes are:
a) Trijicon ACOG's. Never had one fail me in any lighting conditions even though it has no electrical backup. Offers ambient and Tritium illumination and an etched reticle. By far the best illuminated sight I've encountered bar none. They are expensive, and magnified though. A compact ACOG in 1.5x is nice on the PS-90.
b) Trijicon TriPower. Amoung the best reflex sights but there are still lighting conditions they fail in. Offers battery powered illumination for those relatively rare conditions. Wish they would etch the reticle though.
c) Leupold Mk4 CQ/T. Variable power, etched reticle, battery powered illumination. A bit big an heavy but reliable.
I've had many other products that I've tried and liked. Aimpoint, Eotech, Bushnell, Zeis, Dr Optic, Trijicon, Leupold, and a number of inexpensive off brands. But I've always come back to the three models above for something that could potentially save my life some day.
So, don't forget Murphy, and be safe.