I use Wheezy because Jessie would still break things up to a few weeks ago, Ubuntu doesn't have a social contract and would mine user data by default if they can find a way to get away with it, Mint has a Flash binary blob by default (and probably a lot else I don't want running on the machine), Fedora has an inferior packaging system, and Arch sounds like a royal pain.

Pulseaudio isn't designed for low latency (or at least not designed for latency as low as Pd users typically try to get).  That doesn't mean I'd necessarily run into problems with a screencasting demo.  But Gnome itself doesn't have audio recording included with their built-in screencasting tool, and the workarounds evidently have workarounds for the bugs they introduce.  I'm sure I could get something up and running, probably some trouble and frustration; at the moment it's way easier just to explain that I'm yelling "Ka!" when the pendulum in my screencast turns red.

-Jonathan