ExtremeControl seems to be stable. We haven't installed the latest one yet because the building is not ready to take any IT equipment, but we have ExtremeControl deployed in other places in the same area. However, I can't speak to the stability personally, because I'm not using it. I am only the project manager.

It is quite stable, and I rate the stability an eight out of ten.

It's a stable solution. 

The solution is stable.