Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
JB 2.1 works great for me on a first gen iPhone. No more keyboard lag, no contacts lag, no more Safari crashes, and double the battery life over 2.0.x.

I recently noticed the extended battery life too..with 2.0.2 I could only watched 5 of 43min episodes before the battery runs out..now i can get to 7 before I get the 10% message
 
Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_1 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5F136 Safari/525.20)

I found my phone to be a bit sluggish after JBing. Maybe it was the font replacement. Maybe it was the theme. Maybe it was any one of the host of unwanted/uneeded apps that QuickPwn installed (without asking).

I went back to stock and the phone is feeling snappy again. Yes, snappy. Most noticeably, the 2-3 second delays in opening and closing apps is gone.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.