A quick question about jailbreaking

I been unlocking/customizing my phones since 07.

This was my evo I had with miui last year. I love the way apple interface looks.


Now I never looked into jailbreaking, but I know its a kinda of open source programing. How does itunes and my old apps function with it etc, so why should I jailbreak my phone when it comes available? I find that the iphone 4s runs much better then my evo 4g and any touch pro/touch pro 2 etc. Thanks in advance.

 

I might try it tho