Well, naturally it will drain more since it is doing more now, clocking faster, working harder etc - but that droppff does seem a little extreme. Jailbreaking the iPhone probably puts the battery drain on par with the Incredible, Thunderbolt and other high end Droid phones. That was my only beef with Android was the battery life suxxored. I switched to the iPhone 4 last fall since I already had the iPad 2 and wanted to utilize the Cloud and streamline my music and other things. I didn't root the Android because battery already sucked and I probably won't jailbreak the iPhone for fear of battery issues. Its the one pro of iPhone that I love. If you get those issues sorted out please post.
Yeah, I thought the same thing.
In the last hour, I spent about 30 minutes browsing Twitter and facebook as a test. I have Weather Live, Sportacular, Google Talk+, Stanza, Twitter, Facebook, Reminders, Mail, and Phone running in the background. I have a reminder set for when I leave work, so my GPS is running as well. It dropped 15% in that time. Not that bad. I think that's pretty close to what my battery life was before I ever jailbroke. It may be something like 10% worse overall, at worst.
Later, I will run at least an hour-long "Pandora Test" and let you know how that goes.