Being that this phone is only a few weeks old could have an effect. Other variables to consider at my place of work is that I have a tower about 300yds from me and I use WiFi for data while I'm here.
Since my last posting, battery still holding at a solid 80% after a few levels of Angry Birds.
The percentage could be off a lil due to this particular rom, but by the time I get home (7pm), I'm still only between 60-70% so I assume it's farily accurate.
Now, on a "busy" day for the phone where I'm talking alot and streaming music, it'll be a lil less, but can still manage to make it home with 40-50% remaining.