I have 3 of them. holds zero. shoots the square every time. returns to zero with diff weight of ammo I use. No parrallax. I had one mounted on a post ww2 Parker hale 308 ultra lite, for about 2 years. except when i re zero'd to confirm, with South african ammo, I never once had to move either knob during that time, to be dead on , for whatever ammo i was using. I highly recommend them.
midway or midsouth has them now and again for about 80.bucks, which is a steal. They also have a mildot, duplex reticle. perfect for my holdover to 200 yd drills, on my 17's.