I think Fring has an advantage in that communication goes through fring's own protocol through fring's own servers, and fring's servers handle the connection to msn and such. This allows Fring to optimize the phone<->Internet protocol for maximum power savings. This can be a factor of 10 difference on 3G, even if the amount of bytes transfered stays the same.

Once I find some spare time, possibly around 2035 or so, I'm going to write a proxy to cut down on IRC's power use a bit...