I ordered a 20 dollar red dot sight from NCStar as a temp sight for a 12 gauge that was cut down (not by me) to the legal limit and had no proper bead sight on it, needless to say it was about the worst thing in the world.
Number 1, no clicks for windage or elevation adjustment, just twist that set screw and hope.
Number 2 if you turned it towards the left it went left, to the right, it went left, up it went left, and down....it went slightly up and to the left. By the time I adjusted it for a good 15 minutes I had to look at the sight at a 45 degree angle to see the dot and couldn't get it moved back over (slight exaggeration but it was pretty bad) so needless to say I just threw it out and was a much better shot using just the notch down the center of the UTG picatinny then using that NCStar thing.
I have 2 center points on my .22LRs, one is 2-7x zoom and another is 3-9x zoom, no complaints, been dropped, banged, scraped and stored for awhile and are sill zeroed in so as far as that goes they are ok so far. Never used them on higher calibers. I like Tasco red dots, they work pretty nice for me so far, I have one on my AK.