So having purchased Co-Pilot I decide to give it a go from Gloucester to Bristol (my work journey) - midway through route I am on the M5 and it flashes up that its lost its GPS signal - this went on for a good 5-10 minutes and it just did not seem to come back!?!? (I have used my Tom Tom countless times along this stretch with no issues; in fact my Tom Tom has never lost its GPS signal). I basically would have missed my junction (M4 from M5) - Even Google Nav would have at least remembered the route; co-pilot completely gave up. I managed to get it back on track a little while later by closing/re-opening the application, so I don't know if this was the app or I just somehow picked up the satellites again. The device was showing a H signal and the icon for GPS on the top status bar throughout. Once it was back on track it was really good and recalculated immediately when I deliberately chose to divert from route.
I am hoping its a one off, but I am starting to think that Sat Nav on mobile phones is pretty dire by comparison. Anyone else have any issues?