I've never seen one in the air. There's a prototype at a museum at Brandywine in PA which I visited a few years ago.
I just missed Bell's demo aircraft which floated past my school on its way to Paris in '81, just a few seconds after I disappeared into a maths class. Several years ago my MD and I were working on a bid one swealteringly hot Sunday - the A/C was off, so we had all the office blinds closed against the sun, heard the noise of heavy choppers going past and ignored it - yep, two V-22s had wandered by while visiting for Farnborough/Fairford (neither of which I bother with!)