Having used my classic extensively for last three years, achieving 350 hours with it on SD. The only issue I had was drop out of satellites at Fenland, pilotaware would not function. Had to switch over to galaxy tab2 internal gps to get navigation back on line. NOTAMS did indicate fast jet exercises nearby.. Why would paw gps drop out and tablet gps work, latest software updates on all items.
Now completely changed to Rosetta unit, no issues but only 20 hours on it. But impressed with what it detects especially gliders, now able to re route flights to avoid the masses.