I agree.
i tried two 'cheap' optics on my rifles before. One was an airsoft Aimpoint clone, the other was a 'famous maker' 2-6x short scope that was sold as a rifle scope, not airsoft by AIMsurplus.
Given, I used them on my tactical AR, but with the NATO compensator and hydraulic buffer, it has the same if not less recoil than my PS90 does.
The aimpoint clone, losened up the optics internally after about a mag and a half, so 40-50shots.
The AIMsurplus 2-6x scope, survived about 120rounds before the focusing/magnification piece that you turn to adjust it seperated from the inside, making it stuck at 4x.
(On another note, I bought a second 2-6x scope at the same time, and that one is still in one piece after 300rounds on my AK74 bullpup.)