Control panel responsiveness: Does the scope respond quickly to inputs or does it have to think about it for a while?
Control panel layout: Are the various functions clearly labeled? Does the user have to refer to the manual even for simple things?
Display speed: Turn on a couple of automatic measurements and check that the display speed remains fast enough to follow changing signals.
Aliasing: Does the scope produce an alias when the time base is reduced from fast to slow sweep speeds? How does the display look for the toughest signal?