Sorry for the trouble again but a lot of poeople seems to be avoiding to root their android devices. Is there a reason behind this? Voids warranty is that the only concern or is there a possibility that the phone could be bricked in a random time?
I'd say in answer to this, from my own experience, that some people (me!) stay away from rooting because there are so many horror stories on forums about people bricking their phones.
The SGS2 carries a much lower risk of bricking than say a HTC (due to unlocked bootloader, afaik), and using CFRoot you can do it 99.9% free of the risk of bricking (I've heard the only thing that could go wrong is a power cut mid-way thru, but am open to correction). Also, the root methods are becoming more elegant and user-friendly.
I think most of these stories are old or on other manufacturers phones but by simply browsing material on root you come across them and they give you the heebie jeebies worrying about bricking
There's much less risk in 2011 and with a SGS2.
There is of course the issue as well of voiding warranty but the phone can be returned to unrooted status if required. Maybe not everyone knows that.
Personally, I rooted first time in 2 minutes without prior experience. It was easy, and I would say if you follow the CF Root instructions you'll find it very difficult to go wrong (disclaimer!). I tired a couple of custom ROMs, but I have gone back to Touchwiz due to personal preference. I've yet to try Litening and this Siyah kernel everyone's talking about, but I will some day. Even though I'm back on Touchwiz there are useful apps you can only use with root. To get an idea, search the android market for "root" and see what apps there are that require root.
Basically, go for it if you fancy tinkering with your phone. Try not to panic if you get a boot loop as its easily fixable, and do a nandroid