I got this EJ092AA HP 12 cell Ultra-Capacity Travel Battery yesterday. I charged it for around 14 hours, and checked it out. My primary Battery was also fully charged.
I gave a hard time to them: CPU was running around 50% and memory around 30% all the time.
The result is a total of 4 hours (and 4 minutes) runtime with the 2 batteries used together.
Just in fact:
The 12 cell ultra-capacity battery adds + 0,803 kg-s to the 2,1 kg-s Alice already has. So it's nothing that you can call funny. I can hold it on one arm for no longer, and it gets out of balance because the weight is attached on the side and not everywhere. And it looks pretty awful too: the battery hangs out on the back 3 cm-s. I'll try to post some photos, to show it.
Positive is that I got a bunch of AC cables - every kind of specific country types.
I'm still thinking to send it back and buy some simple primary batteries as they are cheaper smaller and lighter. You only have to do a restart when changing them.