The standard 1100 mAh battery of the Axim didn't last much longer than 2 hours while I was constantly using WLAN. I then switched to the extended 2200 mAh battery which allowed me to stay online for another 3-1/2 hours. Like Julie Strietelmeier from Gadgeteer correctly put it:
When it comes to battery life with the X50v, the only word that comes to mind is short.
The PDA unit also became rather hot near the battery compartment after a few hours. I think that current embedded WiFi solutions are still far from perfect, and it won't be before more advanced solutions (
SyChip's embedded 802.11g module) hit the market that PDA's equipped with WiFi will be truly enjoyable.
Still, it gives you a sense of freedom when you can access the Net from any place in the world, even when you're 10'000 meters high up in the sky (see the screenshots I just added).