[flaburgan]

That's a really "proprietary software " point of view. You pay the developers, the price they decided, and you expect bug fixes and new features. As pointed, this model has many limits. I really prefer the free software one, where I am free to try, use, contribute, so then I can estimate myself how worth is a software, and give an appropriate one time or regular donation. This model is so much better.

[morgannewman]

Perhaps this is preferable to the user, but if you consider it from the developer's POV, almost no users will contribute meaningful "donations", so it stops making economic sense to follow the latter model you suggest unless the project is an altruistic hobby.