Found a pretty good first look battery test on the UX90 (UX 50 would use the same battery):
They were done with the default Standard Battery (2600mAh) from 100% (or almost) to 5% when windows decides to hibernate himself.
Wireless was OFF.
Video playing was done with MediaPlayerClassic.
MP3 playing was done with Window Media Player.

With the Power Profile : Power Management OFF

Running 3Dmark 2003 demo with sound in loop i got around 1h24 of battery life.

Running a Video file encoded in XviD 1496kbps (1024×576 29.970fps) with MP3 stereo sound 48kHz 96 kbps in Fullscreen with sound to the max.

with the file on Hard Disk : 1h37.
with the file on Memory Stick : 2h03.
With the Power Profile : VAIO Super Stamina Settings

Running a Video file encoded in XviD 1496kbps (1024×576 29.970fps) with MP3 stereo sound 48kHz 96 kbps in Fullscreen with sound to the max.
with the file on Hard Disk (using headphone): 2h10.
with the file on Memory Stick : 2h18.
Running MP3 files with Screen Off

with the files on Hard Disk (using headphone): 3h20.