I've got a GNS 150 and a first gen iPad mini with no GPS. I had some initial Bluetooth issues but they sorted themselves out and the combo now performs flawlessly with Skydemon. The battery in the GNS lasts for ages and is easily and quickly recharged from the ciggie lighter socket.

I've been using a wi fi only i pad mini for just over a year, with SD installed. I use a Garmin Glo GPS receiver, and have found that combo works fine. Never had any battery time issues, as slam has already stated. The only downside is remembering to take it out of the aircraft, as it is only the size of a Swan Vestas matchbox - remember them - and it can be easily missed on the combing!

My flying buddy uses a 3G i pad with a sim card on SD, and he VERY occasionally has a GPS reception problem, particularly at higher altitudes. I'm not an expert in these dark arts, but a bit of research on t'interweb implies that earlier i pads internal GPS receivers also used the GSM mobile network to improve their performance. I appreciate that this may not be the case with the current generation of 'i tech'.

I have a 2000 which I used to use with my iPad. I lost count of the number of times (in fact make it every time I used it) that I left it stuck to the top bit of the windscreen. I eventually wrote in red in big letters on my kneepad 'Get the ******* Glonass.'

I still used to leave it in...

Once we get GPS tracking chips implanted after birth, we hope it's a Bluetooth one we can use for flying?