I use the Mad Elf GPS with my ipad. Works great.
It was recommended by someone at Gaia (great customer service, btw!) after they helped me troubleshoot why my Garmin GPSMap65 bluetooth wasn't connecting to the ipad.
Turns out the bluetooth function on the gpsmap 65 doesn't do that.
Side note; not a fan of Garmin. After experiencing consistent distance inaccuracies with the gpsmap, I called Garmin customer service. After being on hold for almost an hour, I described the issue and mentioned I had been on a bicycle. Their answer: the unit is designed for walking, not biking. Really?!
Upon further scouring of the interwebz and various forums, I found I'm not the only one having that issue. Apparently that unit is too sensitive to the satellites (or something like that) and will register distance sitting stationary.
All the other functions seem to work OK. I keep it around for a back-up, but know not to trust it for any distance logging. $350+ bad purchase. Won't buy another Garmin devise if I can help it.