Unity lost any good will they built by changing their pricing to per install and making go into effect retroactively. Indie developers especially are up in arms.
Unity changed the license, so developers have to pay a fee for every install of games made with Unity. Notice that it's "install". Not "sale". Not "download".
They claim they won't count installs from demos, cracks, charity bundles, re-installs, etc, but absolutely no one trusts them at this point. Several devs have said they're switching engine, despite the large cost of that.