I've got an iPad holder for a stand, I use it when depping or when we're doing the acoustic duo/trio thing, as there's a completely different song list. But it doesn't go in front of me, I use the bottom of an old stand and it sits by the amp, pointing sideways - I'll look at it to refresh my memory of the song, but then walk away. Only if I've never played the song will I look at it more than that...
I think they look arse from a performance point of view, and let's face it, if we're not actually performing from a visual point of view, we may as well sit down and save our backs...