Not much bad at all! A lot of people dont know that this is the same as the old Bausch and Lomb 4000. I have one on my .220 Swift and just bought me another to put on my .243 AI that I am putting together. In my opinion they are one of the very best dollar for dollar buys in the optic world.
Now then, no side focus (no biggie for me) and they have 1" tube (again, no biggie for me) instead of the more common nowadays 30mm.
But great glass is great glass. What else to say about that?