questions about moving to android

Hello everyone, I'm a samsung symbian (very old phone with a torchlight) user and recently have been considering a move to android. Out of all the android phones I am most impressed by the samsung galaxy S2 (unfortunately for me the galaxy nexus is too large and has a poor camera). But I still have a few questions:

1. I'm thinking of replacing android 2.3 on the galaxy s2 with ICS. I have heard that samsung uses something called touchwiz. My question is, is there anything you would miss in moving from android with touchwiz to stock android? Any samsung special software or whatever that makes touchwiz necessary or desirable? Is it more advisable to wait until samsung updates the s2 with ics?

2. Is there a way to improve the audio quality on galaxy S2 since the voodoo sound mod won't work on it

Many Thanks