Bluetooth 2.0 with EDR is 3MBps, thereabouts >80kbps. Not sure if the UX has EDR, but I do not download speeds gets well past 150KBps download speeds with 3G tether.
I know the theoretical edge speed is meant to be 384kbps, but from what I have experience in the past it has been more like 112kbps.
Agree with you though that the 3.5G and 4G techs are far more power hungry than 2G techs.
micropc hardware: sony ux17gp with 390N mainboard with Anh u7700 upgrade core2duo 1.33ghz 1024mb (now upgraded to 64gb SLC SSD Samsung), Intel 4965 agn wireless, upgrade addon 3rd mini aerial, UX37GBN blue housing incorporating improved keyboard
OS: Linux Ubuntu 10.04 lucid & now 12.04 Precise Pangolin!
sony 380N stock 1.33ghz, 1gb ram, and 40gb rotational drive OS: windows ultimate
light slim notebook: toshiba r200 1.3ghz 1.2gb ram 64gb photofast v1 ssd oS: linux ubuntu 7.04 feisty fawn