ProTools is so unbelievably lock-in, expensive, and closed, that I can't believe any open source proponent of anything would even touch it.
There is no DAW software as good as Cockos Reaper. It is priced so anyone can afford to use it, any VST or DX effect or instrument works in it without a hitch, and it can offload effects processing, rendering, sample streaming etc to a remote Linux box. And when I say "any" VST or DX plugin works great in Reaper, I do mean ANY. VSTi's that are fussy in ProTools or Sonar or Live or Cubase will be smooth as silk in Reaper.
There is no other DAW that comes close. I started with ProTools years ago when there really was nothing else, worked extensively with Logic, and have completed high-level projects in Sonar, Cubase, Ableton Live and others. Nothing compares to Reaper. The community that supports it is more helpful han professional support from any of the other companies.
Also, Reaper will run on practically anything with a processor. 32 bit, 64 bit, Linux, OSX, whatever. I teach some DAW production, and I tell all my students to get Reaper, so any project will work on any platform.
If you have any interest in making music with a digital audio workstation, you can get a fully functioning, non-time limited demo of Reaper for free. I'll bet you end up buying a license ust because it's so good and so worth it.
Now, regarding the MuseScore project with the Bach performances, this is really great news. MuseScore is terrific and mXML is terrific and I'm looking forward to all the future projects that will use these open source recordings as source material.
The fully OSS community hasn't yet put out a really great DAW, but boy, have they ever made an important contribution to the world of making music.
I would love to see projects like the Bach project with other composers. I'd love to see more enlightened contemporary composers embrace this open source approach.