I don't know anything tecnical to tell you, but I can give you real life experiences. I got my RAZR on 12/31/11 and for the first week and a half I had it set to use 3G. By the end of the day I only had 30% to 40% battery. Last week I changed it ot use wi-fi wherever possible. Right now at 4:55 PM I still have 80% battery and I have used it all day for checking and replying to e-mails and I have noticed several app updates throughout the day.
My daughter who uses her Droid 2 Global to play around on FaceBook and Twitter, for what seems like all day, also changed to wi-fi and she has 40-50% when she goes to bed where she was dying around 7-8 pm with 3G.
For us, we are staying on wi-fi whenever we can.