Just tested stremium on their testnet. The audio-quality is like 96 kbps. No really good for streaming audio. I didn't test video, but I think it's slow and not usable for stuff like "instrument lessons". If the quality of the stream will be better, this might be a great thing.

I also had problems with connected to a test-stream I created. The problem was, that NoScript blocked some sites you need to watch / hear the stream. The problem was, that I paid for a session (20 minutes) and after the payment was received by Stremium and I landed on the stream-page, I had to allow some sites / scripts and after that, the site reloads and I wasn't on the streaming-site anymore, so I had to pay again. I don't know, if the payment from the first time was paid back, but that's a big problem at this moment.