Im doing a side by side comparison test to see how each perform. DAY 1 The 3G is a 16GB model and is jailbroken. 3G radio is ON in Data Settings. The WIFI is a 32GB and is not jailbroken. Brightness is set at 50% on each. Volume is at max. Location services is turned on. Test #1: Playing a streaming movie off of Netflix (Les Miserables) over WiFi. Started at 11:48AM. I'll keep this updated as the day goes if you want to check back in. 1 Hour In: 3G: 96% Wifi: 98% (2% difference) 3 hours In: 3G 82% Wifi 85% (3% difference) 5 hours In: 3G 69% Wifi 72% (4% difference) - I started playing a new movie, Monsters, Inc. as it's not a dark scene movie and it is full screen (vs. dark scenes and widescreen in Les Miserables) 8 hours In: 3G 43% Wifi 49% (6% difference) 10 hours In: 3G 26% Wifi 34% (8% difference) 12 hours In: 3G 9% Wifi 19% (10% difference) - Test stopped at 12 hours. Day 2 Same test as yesterday but now with 3G radio set to OFF in Data Settings. Test started at 8:10AM. 1 Hour In: 3G: 98% Wifi: 98% (0% difference) 3 hours In: 3G iPad: 83% Wifi: 84% (1% difference) 5 hours In: 3G iPad: 68% Wifi: 69% (1% difference) 8 hours In: 3G iPad: 42% Wifi: 44% (2% difference) 10 hours In: 3G iPad: 25% Wifi: 28% (3% difference) - Stopping the test at 10 hours.