I've heard about Muscula (and I'm reasonably sure they've heard about Errorception - it's a smallish world :) ), and I'm curious to know more about how they do what they do.

That said, the architecture isn't too different. Errorception is also built on Node and MongoDB. I am not a fan of JSONP (GET) for writing data (POST/PUT), mostly because I'm a stickler for HTTP semantics. Otherwise, without too much insight into what Muscula is doing, it certainly looks like we are very similar.

Browser/OS information is rather easy to get - it's all in the UA string. Errorception captures that already. :)