They're heavy - 90kg IIRC. Require 3 people to lift.
We have a couple of them around the school here, and the teachers who have them like them.
However, they are still a *little* expensive when your budget is being squeezed. So, we've had to switch to using Epson EB-485Wi projectors which are about £1100 a go. We install them ourselves, as they're put up with a couple of screws. Pair them with a normal whiteboard and you're sorted.
However, you'll want to stop using SMART Notebook with them due to the preposterous pricing of their 'non-SMART license' to use their software on them. (Something like £800 per device per year...).
In an ideal world, I'd be swapping the 65" Clever Touch screens into every room that needs one.