Sadly, it being free is likely to mean there are lots of things missing. I spent some time with CoPilot some months ago, and found the same. The author invited me to generate a list of data for the missing airfields; I was going to do it by downloading a lot of pages from the AIP but in the end didn't have the time. So it wasn't really usable in the UK.
So I have stuck with Navbox Pro. It costs a bit of money but is very accurate. Avbrief for weather, and the AIB site for Notams. It would be great to have a PDA with a 640x480 screen and GSM (and battery life more than 10 mins...); then one could do the lot on the move.
For the money one spends flying, there is no point on skimping on these things, IMHO.