I was gifted one that I use on my Nikon FG body occasionally and the length is just too long, I think. It's never crappy or wide enough.
(Cue Diana Mini, which is often too crappy.)
I've been tempted to borrow someone's fisheye adapter and see if that helps, but as DS said, I should really just buy a Holga.
EDIT: Just out of curiosity, has anyone tried the Diana lens adapters on a film SLR?