Run two vipers, a pst on my target 22-250 6x24 ffp, and an hs 2.5x10 on a 7 rem mag. Also run a crossfire rimfire on a .22, own the diamondback bino's and the rangefinder, and am ordering a razor hdII for my new target rifle.
Also have owned leupolds, tasco's, nikon's and others. I also work part time at a retail store where we sell a lot of brands, and by far the biggest seller is vortex. That being said, ive seen a few come back with some issues; fuzzy optics, cant maintain zero's, interior flakes, etc, but, that is few and far inbetween. If i were to wager, probably for every 250 sold, i hear of a single issue, and thats a rough non scientific guess. Other brands we sell have fewer issues, but we sell very few of them, be it leupold, bushnell, stiener, burris, etc. Once in a while id hear a comment back about a steinier that had to go back, a burris that went blurry or leupold warranty center issues, but they are rare. If all being equal, id say they have about the same failure rate as vortex, again, a non scientific calculated guess. That being said, the more of something that is out there, the more problems you may run across. It works that way for cars, computers and gadgets.
I own them, because they are priced right (and an instore discount helps). And from my personal experience, they work. I havent had a single issue yet to date, and while i dont outright abuse my stuff, they do get used in a variety of environments and conditions. I do believe however, that you get what you pay for. If money was no object, id probably be dabbling in mark 4 and vx6 stuff, but just cant justify the money for the performance just yet. Maybe someday, but not today.