I’ve played scalloped fretboards in the past, and to tell the truth, to me they feel pretty awesome. A few years ago, I almost bought a Tele that had a scalloped fretboard. But after playing primarily acoustic guitar for 25 years before making the switch to primarily electric guitar, my touch is simply way to hard to play a scalloped fretboard.
Believe me, I’ve tried to lighten up my touch, but I still unconsciously dig in. Over the years, I’ve gotten a lot better with my touch but I don’t think I’ll ever get to the point where my touch is light enough to play a guitar with a scalloped fretboard. But who knows? Maybe if I try one in a few years, I’ll like it.
In any case, there are several fairly famous guitarists that have used scalloped fretboards. Most notable – at least to me – is the great Yngwie Malmsteen. Here’s a video of him playing what he calls “Arpeggios from Hell:”