OpenRepos/Warehouse is basically the serious version of the Jolla Store. Many more interesting applications, and much less junk!

That said, I don't think finally having paid apps would be of any help, because they will just keep on publishing the umpteenth note-taking Android application or the endless stream of Tajay Studios, or more apps to find out about the latest stonings in Saudi Arabia (I mean, who doesn't just love that?), with no quality control whatsoever. If I made twenty hello world applications which all had just the text in different colours, all twenty would be published. Jolla's reasoning is that they want to give everyone a chance, but to me this just sounds like a cheap excuse to make the Store look fuller than it actually is. Quality over quantity is completely lost on them.