I have been geocaching with a Samsung Galaxy S2 since Feb and have just ordered a Garmin Montana. I was sick, fed up of an unreliable GPS signal on the phone, especially in tree cover and especially when there was no cell coverage. The GPS signal was always stronger and more reliable when I had a cell signal and could activate a data connection, however in the countryside of Scotland it's not often an option.
I am expecting the Garmin to be an improvement, as far as GPS signal is concerned. I hope I am not mistaken.