it's a bastard to check your blindspot in a hardtop. Easy enough to lean out of the drivers side window (if it's open), but you've got no chance on the nearside. I would prefer windows on my 90 in the back to the van style hard top. Where are you?
One other thing of concern is that you might have to start insuring your vehicle as a van instead of a car if you get rid of the windows in the back!