I was going to put a Sig Romeo 5 red dot on my S2K but then I saw a Feyachi model 22 for less then half the price. Read some pretty good comments on this Feyachi red dot.
Just remember, you get what you pay for. I’ve bought plenty of the cheapo sights and have hated them. I gave most away. I will pay the extra just to know when I pull it out of the safe/bag, it’s dead nuts zero every time.
What is your price point? You can find decent red dots/holo sights for around $100. This is by far a much better bargain sight for the money. I have 3 of them and have never had an issue. They hold up great to full auto/binary 7.62x39, .300aac, and 5.56. Oh and with a .22lr upper, it is easy to hold on target and send tiny lead.
I love the shake awake Romeo5 and 2 moa dot but I have SightMark RD’s too and never had a problem. People who like dot-in-a-circle can be happy with them too and a 3 moa dot is okay for most people. Gets a little wonky if you have astigmatism.