The different apertures are nice. As far as bulb mode and a tripod mount, those are standard on the newer Holga (Holga 120N and later) models. I was reluctant to get one, because they may end up making it better, which of course, is worse. But the lens and light leaks appear unaltered. Also they put in foam to hold the spools tight, and made it a tighter fit on the bottom, so you dont have to shim up the spool anymore.
I don't have a holgamod. Are they worth the extra expense for the few extra features?