electronic V's paper mapping

So one of the big (if not the biggest) question playing on my mind is whether to use electronic mapping or traditional paper maps while pushing for sustrans.

When i say electronic, i am specifically looking at mobile phone mapping software rather than a hand-held GPS such as Garmin. This is to cut down on items to carry.
I have in recent weeks acquired a motorola running the android operating system, thanks to an overdue phone upgrade. Now i am mightily impressed with the google maps app embedded onto it, and the GPS tracks me well. This is very handy right up to the point where i loose 3G coverage and the map fails to update, which could be a problem.

Paper maps don't have this problem, but am worried about the size of small road maps, and/or the amount of OS maps i'd need. i need to look at paper maps and see what's offered these days and what details they have.

Another handy thing with my phone is the amount of useful apps out their for plotting and tracking on maps. might be hampered by battery life but unlike the iPhone i can carry a spare battery :) android 1 : apple 0

regards