Tom
Yesterday was my first flight with the Stratus II as well. One way to tell if the gps is working is to see if the artificial horizon is up and running. I found that he gps signal is acquired very quickly. The radar, me tars, tags etc all work as advertised. The Horizon works well but you need to download the Stratus Horizon app to be able to "level" your screen. It does not seem to be possible to make this adjustment through Foreflight, which would be nice, but is easy to do with the horizon map.
One possible concern is that with the Stratus II working and connected by wifi to two iPads in the cockpit both iPads got too hot and showed the "need to cool" screen before they could be used again. Both units were in the sunlight but showed the hot indication much sooner then I had experienced before. I wonder if the extra power required is causing this situation. If that is the case perhaps plugging them into the airplanes power system might help?