As one of Vuo's developers, I work on Vuo's engine (the thing that makes compositions run), work on nodes, and write documentation. You'll see me on the forums answering people's questions about Vuo.
I've been developing apps and frameworks for several years (since I was in college). Pre-Vuo projects include Kineme Quartz Composer plugins, iOS apps for education, an app that analyzes photographs of tomato slices, and software to help people with disabilities use talking keyboards.
I enjoy using Vuo to make live music visuals. My hope for Vuo is that it will grow into a community of people of diverse backgrounds and identities making lots of different artistic, useful, unique, goofy, beautiful, crafty, wonderful compositions.
It is sometimes/unexpectedly/itermitently grinding to a halt and I can't determine what is wrong.
Oddly it looks like NI mate is sending a lot more OSC messages than it says (instead of 30 fps, about 120 fps, which is around 1,200 OSC messages per second). That's a bit much for Vuo to digest. Adding a Hold List node, as in the attached composition, should help.
Unless I'm missing something, you could skip the Get Mesh Values and Make Mesh with Values, and maybe improve performance a bit.
I tried export as an app but the audio didn't play...
The problem is that your audio file didn't get copied into the app. Vuo can automatically copy audio files in some cases, but if it misses your file, you can copy it into the app manually. See the manual section Exporting an application.
Now that you've done the hard parts (like breaking down the problem into well-defined small pieces), I will just add a couple of suggestions to sidestep some of the duck yuck.
One is that you can form a list of 0s and 1s using Enqueue and turn those into fading-out opacities by multiplying by descending values. (Actually since the Enqueue output is oldest to newest I'm multiplying by ascending values.) (See ConcentricCircles1.vuo, which by the way is not very efficient.)
The other is that you can get times relative to the timebase (or a timebase? not sure if this is the same as what you were doing) by subtracting them from the current time, again using list math nodes. (See ConcentricCircles2.vuo.)