Folks at blogeee.net have published a review of the eee pc 900, with in depth battery benchmark. Results were more than poor [Update:new batteries,better results]
Their eee pc 900 were shipped with 4400mAh batteries, a consequence of a battery production slowed down by an LG factory fire.

The eee pc 900 with a 4400mAh battery did last 1h 22mn for an office use, with wifi enabled. Using a 5200mAh battery did enhance the performance to about 2h10mn while an eee pc 700 with the same battery will work for 2h50 minutes.

The worse performance was for reproducing multimedia files. An eee pc 900 with a 4400mAh battery will play an xvid file from a usb pendrive for only 50mn!

eee pc 900 battery blogeee.net benchmark

This is clearly a problem for a device meant for a ultramobile use!

Hopefully, the well known umpc blogger Brad Linder has reported good news about new battery production. The battery shortage should end by Q3 2008.

Photo and benchmark credit: Blogeee

UPDATE - 05/14: Tests of new batteries at blogeee have shown much better results for the eee pc 900:

  • 4h of surfing with a 6600mAh battery
  • 4h18mn for an office use with a 7350mAh battery
  • 3h07mn for watching DiVX with a 7350mAh battery

So, hope is not lost, and good performances can be archieved with quality batteries.