I am using it, we have been testing it for a few months now and have worked pretty close with the crew over there. They have been very responsive and helpful in getting things right for us. The panel is as close to ease of use as I have seen to a CPanel like interface for windows in features and ease of use.
MUCH MUCH better and easier to use than HELM if you are lookng for a stand alone server config, it is very good.
Yes, am using Inspanel. The team are very helpful and the software is excellent. I would advise a fresh install on a new server as I had a few issues trying to use an existing server (against Inspedium advice). I would recommend to anyone.