Jailbreak Query.

None.

But then gain, it depends on what packages you install. If you start installing "cool" things that eat clock cycles on your phone, it'll drain the battery faster.

As far as I can tell, having OpenSSH, Winterboard, SBSettings, etc installed has no impact on my iPhone's performance.

 

JB only won't cause performance issues. It's what you installed or change that could cause it. I don't notice any performance issues, but then again, I don't install much stuff. And, the apps I do install are mostly popular tested which shouldn't cause any issues.

 

Umm, in my opinion Winterboard is a battery eater, but not by too much. Just thought I'd put it out there.

 

lots of threads already and one already on this page that is quite good also google works fantastic oh and youtube. sorry I'm not a big theme guy every once in a while I play but then I go back..

 

Winterboard can be hard on the battery if you overdo it. I only use it to replace a few icons and I don't have any battery issues. Really depends on how you use it.

 

winterboard + other graphical mods will drain the battery more, + use cpu and memory

the iPhone 4 is fast enough to not notice the extra strain but its definitely there ( try doing it on an iphone 3G if you want to see a bigger difference)

There is no major risk, if it crashes it will usually restart in safe mode, so there is hardly ever a concern for long term issues

I say go for it if you want, but I think like a lot of people you will winterboard your phone, but then probably after a few months go back to stock due to random instability issues