Is it worth upgrading my jailbroken 3G to iOS4? I have a jailbroken (not unlocked) iPhone 3G running the 3.1.2 firmware. What are the pros and cons of upgrading this to iOS4?

Being jailbroken, I already have multitasking and home-screen wallpapers. What does the new iOS give me that I don't already have access to?
I've done it and it's not worth the trouble.  I'm considering rolling back to 3.1.2.

The beneficial changes are minimal (and most can be provided by a jailbreak app), and the performance decrease is very noticeable.  I've found that crashes are much more frequent as well.

My advice: Don't do it.