I used my Iphone. I first tried out the free app... and after i got my 3 caches upgraded to the paid. So glad I did. I also use the battery pack. I bought it when I got my phone and its coming in handy now that we Geocache. I too found some areas are difficult when you lose cell service and when I had the death feeling when I watched my son start up a bunch of rocks to find a catch and threw my phone at me to hold, I decided it was time to get a stronger GPS, So I decide to purchase a Garmin. I went in with a plan to get a decent GPSr and ended up with a great deal on a Oregon 450t. with this I can upload the caches before we leave and dont have to rely on my phone. I prefer my Iphone but I think it may be because I have been use to it. The last few caches I've done was puzzels or out of service areas and I think the GPS would have helped out more!
