I can tell you I have tested the Arken scopes tracking against some of my other quality glass and the Arken's I have tried tracked very well. The target bellow was a straight come up from a 100 yard zero to an 600 yard zero, put on a little windage and shot three They track.
I have one from the Classifieds here. It's on a 22 Target rifle. For the price of them used, I think it's a great value. I am not out here cranking turrets a lot so can't comment much on that. I've heard the EPL model is awesome.