I got my LR-17 from One Shot Tactical. They are the distributor.
Buy an SR-25 from OST while you are at it. The LR-17 looks real pretty on top of one.
The USO is definitely in the same league as my S&B 50x in terms of tactile feedback on the turrets, and the EREK knob is my second favourite knob to play with. I don't see a difference in the glass quality, but I have never used either scope in low light.