They offer a precision tracking guarantee. All 4 of my Arkens (3x SH4 Gen2, and 1 EP5) track true. I own German SCHOTT glass scopes as well, so I know alpha glass. And for the money, the Arkens have impressed me in the budget scope (sub-$1,000 MSRP) category.
I ended up just pulling the trigger on a 6-24x50 EPL4 MIL VHR a few minutes ago. I figured with the combo pack and free shipping it was under $450... I've wasted a lot more than that before on junk that was supposed to be good, that I basically had to give away, because nobody wanted it either.
Plus, they offer a precision tracking guarantee, they have good customer service, a satisfaction guarantee, and since you buy directly from Arken (no middlemen), they will send you a return label and issue a full refund if you're not satisfied. The way I look at it, is that it's kind of hard to lose in that situation.
If it's great, then you got a good scope at a great price. If not...You get your money back.