What filaments work?  

Re: What filaments work?

Has anyone here actually gotten the MMU2 working with stock setup & software? If so, what filament/temperature?

I've been using Inland PLA, Priline TPU, and random ABS successfully with a stock MMU.

Re: What filaments work?

Has anyone here actually gotten the MMU2 working with stock setup & software? If so, what filament/temperature?

Yes. I ran first couple weeks without any mods and currently only filament holder are replaced. Everything else is still original.
Even if everything is still original on my unit, I had to adjust couple things which are not mentioned in the Book:
-> adjust the FINDA position
-> adjust screw tensions
-> made sure filament path is running clean
-> find the right temperature for your filament

For the first three items, go by the book first. I can explain the details once you encounter issues.
Regarding the last, I would recommend you for the first tries to go with PLA temp as low as possible. Forget about any recommended values. Print a temp tower until you get clicks. Then raise the temp by 5C. With such a low temp you should get pretty nice tips. It should help to succeed right away.