I have two 4200s and their tracking is very repetitive and predictable. Have owned them for over 5 years without any issues so I can't comment on their customer service. Only complaint I've ever heard about them is that their eye relief is .2" less than others in their class. I've never noticed the difference when comparing them to other comparable scopes. They are not my favorite scopes but I wouldn't hesitate to recommend them for their value, quality and durability.
YMMV.
