I also had a reticle break on a couple of M8 Leupolds (though one was my fault, due to farmer-tightening rings), and had an ancient 8x36 M8 fail to hold zero after about a zillion shots.
Have also owned a number of Leupold variables that never had any problems, including several still on a number of rifles. But in the last decade have had to send at least 4 times as many Leupold variables back for repair as fixed powers, and I have as many fixed-powers on various rifles. Have found the 1-4x and 1-5.5x variables very reliable.
Probably the most reliable "affordable" variable I've used in sufficient numbers to provide a reliable sample for is the Burris Fullfield II, and haven't found any difference between the American-made and Phillipine-made versions. Like dennisaz, I had a 2-7x on a .300 Weatherby for several years, though not as long as he did, with no problems. In fact have never had a problem with a FFII. But that doesn't mean I believe they're unbreakable.
