I only listed ones that are directly comparable with the latest version of Alt.Binz in terms of features, including integrated search, which excludes vanilla Grabit and SABnzbd (both are comparable to 0.25.0 in its current state). Feel free to add any more to the list if they meet the criteria.
There's nothing 'up in the air' about the donations system, and Alt.Binz is not a commercial product. If it was, you can guarantee that the price would be way higher than the typical donations received & accepted, which are a lot lower than those other apps. A minimum isn't specified, as this would become a de facto price. Only those attempting to donate tiny amounts are rejected. There were 50 attempts to donate 0.01 euro last week, which after Paypal fees = 0. It's not difficult to understand - and 1,600+ Contributors seem to have managed it without complaints so far. The truth is, Alt.Binz is still the best bargain out there.
Anyway, I'm breaking my own rule by talking about what's been discussed ad nauseum elsewhere in the forum, and I'm boring myself to tears just reading my own words.