Do it, the only people that say dont have not done it!
I can record videos, the camera is better (i have a different one which has more features) i can upload videos and pictures wireless to my computer or directly to youtube,photobucket and facebook. I have cool themes and sounds (unlock sounds, txts, ringtones) various cool apps you cant get on the appstore, i have mms, i can forward txts, i can copy and paste in safari (and other bits that are usually annoying)
Heres a random vid i just uploaded to photobucket (not bad for a phone with no videorecorder)
Do it! It makes the phone what it should be, its pants unless its jailbroken!