I like them - on semi-autos, anyway. I have a Burris Fastfire III on a Glock 10mm, and a C-More STS on a .460 Rowland 1911. So far the C-more appears able to withstand the punishment of being slide mounted on the .460. They are fairly small, generally don't interfere with use in a holster, and target acquisition is fast. On my hunting revolvers in .44 mag and .45LC, however, right now I am using scopes - although I might well switch to a holo sight at some point.