Bought the GS3 soon as it came out. Prior to LTE turn on, I left WiFi on for our companies connection, connected to 3G at about -96dB (2-3 bars) I would drain about 60-70% battery in a day, leaving about 30% driving home.
Now I am on LTE coverage all day at work (-105db, 3 bars) and drain about 40-50% battery with WiFi off over 8 or 9 hours. The past three days I have left with over 50% battery, about the same use. Could be due to the fact I don't need to use wifi anymore, not sure.
At my house I am on WiFi and an Airrave that gives crap for signal (-95 to -110dB 3G/1X) and my battery drains much faster, just like my old phone. At my girlfriends apartment I get 3G only, but about -60db signal (full bars, tower across the street) and I'm pretty sure my phone can't die there. Last weekend I got 18 hours using WiFi under heavy use. No LTE there yet sadly (I can force a -120db connection but it's not really worth it).
In comparison, my WiMax phones (OG Epic and Epic Touch) would not last the day at work on 3G or a day at home. At the girlfriends house, the Epic Touch would make it a day, unless I turned on WiMax. WiMax was great at her place, full signal, but as far as battery life I'd rather not talk about it. To the guy who made the comment about running a USB toaster off his phone, I disagree. I could only really use WiMax if I plugged my phone in, and with the power draw of that radio plus the charging of the battery, I'm almost positive I could toast some pop tarts WITH my phone, no toaster necessary.