At the end of the day, I don't believe there's very much of a difference in
how your DAW performs. Time taken in Gentoo, may be time taken in a
different form on another distro.
From personal experience, my very first _hobby_ project
before I started out
in the audio industry was to set up a Linux studio environment
with Gentoo.
I ended up victimised and gave in to the CFLAGS club while never having
gotten anything done. That was the period of my life I wish I could fix. I
learned nothing except compiling. Whatever satisfaction I got was placebo,
and whatever time I'd used (I won't call it "wasted") could've been
for
something more beneficial.
There are certain applications for source-based distros, like for eg. a
server environment where your _job_ requires that you compile. Other cases
are merely education-related or personal endeavour. For the few that are
successfully running studios with Gentoo-based platforms, they have their
reasons and it works for them. I doubt they question their own efforts and
were ever in a pathetic position.
Suggestions:
Debian
Sidux
Arch
Caveat: I'm an Archer =p