This thread sums up a lot of the talk around the web nicely. Most people who say Leupold works great are the ones who usually never dial, don't shoot past 400, and quite frankly, wouldn't know if their gun didn't return to zero or was off by a little while dialing. If you don't dial, Leupolds usually work great.
My entire life I used Leupold because that is what my dad had always used. I was happy and didn't noticed any problems because shooting longer range and dialing a scope wasn't a thing for me back then. A number of years ago I started shooting much more often and started messing around with shooting farther than I ever had. It wasn't long after that I started to notice all was not well with my Leupolds. The RTZ would be the most common issue I noticed after a session with lots of dialing. Since then I haven't purchased another Leupold and most likely never will until they start earning a reputation for durability with the "dialing" crowd.
With all that said, there is no other scope brand I would love to see return to their former glory than Leupold. I think their MK5 line would rule the market if they would take care of the rtz, and to a lesser degree, the tracking problems. Glass, eye relief, turret feel, weight, and price....the MK5 is arguably one of the best buys in that class of scopes. I wanted to buy one so bad for my latest rifle but I just couldn't risk it. The only thing holding the MK5 back is their durability and repeatability.