Nice review posted. What I found in both is:
1. for processing S2 has got faster processor and RAM. = S2 Wins
2. Video rendering. = iPhone 4S (this is something related to Android/iOS)
3. 1080p Recording = S2 definitely better
4. Tapping applications on both = iOS use transition between 2 screens while android is flat. iPhone has beauty and Galaxy S2 has fast response
5. for Voice SIRI wins. It gives response if you are jogging or unable to look at the display for any reason. (blind girl using iPhone in Apple ad) Unfortunately we have too much noise around SIRI will get mad
6. Built: iPhone 4S has Glass on both side like iPhone 4. look sexy but most of people use case so they don't drop it, and there is nothing sexy in a case.
7. Built: S2 very much plastic.
8. iOS offers iCloud such an incredible service with 5GB free. no need to hookup with computer, your data is secure on Apple's server. Not sure if Galaxy S2 has such a service.
End notes: What I understand from reviews about phones and gadgets, companies look at US/EU market and culture when build a phone or gadget (specially Apple) Tablets are the biggest example, people carry tablets in subways, trains and in buses. These phones are not expensive for them as they get it in $100 or $200 and rest on easy installments subsidized by Carrier. For a Phone 3.5 inch screen is enough. Bigger screens make others feel like you are carrying tablet in your pocket. Phone should be less complicated, trouble free and with reasonable features for price. A consumer is not going to make a Hollywood standard movie so 1080p/30fps is useless if you can't share it on 1080p Display. Most of people buy these expensive phones but unable to do more than call/text or if they learn to take pictures, next biggest problem is how to transfer. Not everyone is geek in this world. Companies should provide unique features to help people ease in daily life rather than beating each other in GIGAHERTZ WAR.
This is my opinion, you may disagree, no offense
I am Apple fan but this review is very much unbiased