I have used 3 or 4 over the years, including a 2x7 Fullfield on a high milage AR-15, without problem. That is a $169.00 scope, new. As was already noted here, the lower priced Leopold's are not quite as sharp and clear (to my eyes), but they almost never fail, and are well known for their great customer service. I have not had the need to try out Burris's life time warranty.
Larry