I have the Trijicon RMR and it is a great piece of equipment. I have the CMore STS and that is nice also. Trijicon is battery free and that is a big reason for the price. If you buy the Trijicon RMR you will only cry once.
The CMore STS is really nice also. You don't have to take the STS off the rifle to change the battery so you won't have to re-zero when the battery goes dead.
Both are really nice and a cut above the rest. The Trijicon is nicer than the CMore STS and that's why the price difference.
Having said that------You can't go wrong with either one.