While I dont own one, I have researched them extensively, spoken to many who have them, and have heard nothing but great things. What they may lack in quality when compared to Aimpoint/Eotech(which seems to be not much at all), they more than make up for in customer service....again from what I have heard. I am told they honor their lifetime warranty immediately with no questions asked.
I bought a Vortex Crossfire 6-18x 50mm objective about 9 months ago. It was one of those deals you can't pass up kind of things. Had it on an AR for a while and really liked it. Wound up taking it off to put a 1-4x on it. Optics were great for the price and it held zero over the 1k rounds of 5.56 that I ran through the AR with the scope. For the price I would recommend it.