I have EOTech, RX-30 and Aimpoint CompM4 on ARs. If you are interested in long range, the 1 MOA dot (inside 65 MOA ring) of the EOTech is hard to beat, along with the fast target acquisition. The RX-30 has a 6 MOA dot and with its 42 mm objective, is ALMOST as fast as the EOTech.
The CompM4 has a 4 MOA dot, and will run 50,000 hours on REPLACEABLE batteries. This is a nice sight but it's an $800 unit, costs about twice as much as the RX-30 or the EOTech 516. While a nice scope, I'm not sure it's worth two EOTechs or two RX-30s.
The RX-30 will run 10-14 years on its tritium bulb which is NOT user replaceable. There is also a LONG wait list for this optic, so if you don't already have one, it may be a LONG time before you see one. Apparently Trijicon is filling their .MIL orders first (I don't blame them)
The EOTech will run (??) hours on its (various different types of) batteries. 2X N, 2X AA, 2X CR123, etc. The EOTech 516 with its CR-123 batteries (used in many tactical flashlights) last the longest.
Each has its advantages and disadvantages. Of the three, I like the EOTech best..