My experience has been with the Sig Romeo 4, Aimpoint Micro, Trijicon MRO, and Eotech XPS2-0. In my opinion you can't go wrong with either the Aimpoint or the MRO, I prefer the MRO for a slightly wider FOV as stated above. I also love my Eotech, but it is larger and heavier than the other options and depending on what its going on may factor, the eotech has taken a beating and held zero, I haven't had it in extreme weather so can't comment on extremes. The Sig Romeo I have only fired in an indoor range while I zero'd the optic for my father and then again the next time we went out, performed just as well as the others under the conditions I have experience with but something about it, that I can't put my finger on exactly, felt slightly cheaper than the others but since it costs only half or a third that of the others I could see myself buying one for range only use, I also appreciated that you could cycle between just a 2moa dot or dot with 65moa ring. Ultimately if it's only for range use they will all get the job done, now if you're going to be doing anything more involved or counting on it when your life is on the line I'd step up to one of the other 3. I'd also consider which reticle you like since the Aimpoint and MRO are 2moa (Aimpoint also has a 4moa) dots while the Eotech has the 2moa dot with 65moa ring. The Aimpoint and Sig both have caps over the windage/elevation adjustments which when unscrewed (which can be done easily) can be used to adjust the optics while both the Eotech and MRO require some sort of flat edge, tool, coin, etc to make adjustments. They all have pros and cons in my opinion, so weigh those as well as the price differences and what you're honestly going to be using it for and make a decision as in the end I'm sure you'll be happy with anything listed so far. Good luck
edit: just reread what firearm it's going on and agree with LCSO264, go for either the MRO or the Micro