I agree with Steve M, some people just want to give money but don't want to / can't help with the development, and others that want to do their contribution to the devs in form of beta testing patches etc. and not money can't do it because they are locked out.
I somewhat agree with gruso that there may be a problem with "ordinary people" complaining about unfinished software, but it shouldn't be a problem if you are clear with that when you release it, that it's just an alpha/beta release and that only people that understand sofware development and can give constructive criticsm should try them.
Also I think that this problem wouldn't completely go away just because you would have to pay to the dev fund, because as said earlier, ordinary non hackers also donates and therefore have access to the closed alphas / betas.
However, something extra for the donators would perhaps make more people donate, and thats is ofcourse a good thing.
Oh, and hello by the way, my first post on this forum.
( I made one post on the gp32x forum, then went into purgatory mode, and I'm still there, even after two mails to hando, (this was before the forum crash))