And I don't mean that as a bad thing, simply that I am mostly unfamiliar with them.
I went with the Holosun HS403 from Brownells I think. Normaiiy I buy from Primary Arms but they were out of these when I wanted it. I think I spent $171 shipped. 50K hours battery life, has an auto on feature and if the gun is sitting still for 3?hours it goes to sleep, you set that timer. Brightness setting, easy to sight in.
That Sig Romeo that is just like the Holosun? I'm pretty certain they are built on the same assembly line as the Holosun. Can't go wrong with a Holosun, for a budget RD. I have on several ARs/rifles a Lucid, Bushnell, Vortex and the Holosun. Hands down the Holosun is the easiest to use and with the 50K battery life, pick it up and it is ready to go, no futzing with an on switch.