I'm not sure how you ended up with a S2 that'll even come CLOSE to the same or actually as you state 'longer' battery life than the 4s! I've owned the S2 and iPhone 4 all year...my wife also has the iPhone 4. Not EVEN Close!!! The iP4 has and has had at least DOUBLE the capacity of my S2, including two of my friends that have the Galaxies.
I just bought my iP4s on launch day. Not a SINGLE issue with battery life. 64gig model...over 200 apps, I use location service, BT, 3g, WiFi, et al. Not a bit of difference between it's life and my iP4. These "bat-gate" comments are truly and magnificently over-embellished! Obviously...when you're shipping this many phones (3.5 million activated *4s* on Christmas day ALONE!), there are bound to be some bad apples. And folks with 'issues' and 'challenges' with their new device ten to speak much louder than those without.
If there TRULY was a battery life issue with the 4s, the outcry would be HUGE! Every review I've seen...not a single one has had the problems sounded by so few. Again. OverBlown! And I've owned two iP4s's....I originally got the 32gig. Used for a week...wanted the 64...they got 'em in at my Apple Store and I exchanged. Was I perhaps lucky? With two phones and NO difference in battery life? Perhaps...but I'm skeptical.
I've also owned a couple of the original iPads. A 16g wifi and a 64g 3g. Awesome Experience...with BOTH! iPad 2 launch day...same, I bought two, 32g Wifi (wife) and 64g 3g (mine). Since launch day, I've had battery issues with my 64gig. Read in the morning, the news while getting ready. Shut it with 94% left, open at lunch to check email...down to 79%!!! OUCH! Didn't happen on ANY of my other iPads...either the originals, or my wife's new iPad2.
Long story short...took the problem iPad to the Apple store last week...the genius ran a quick diagnostic. BAM! iPad was NOT going in to stand by for some reason. Exact quote from genius "I'm NOT happy with this iPad's hardware, I'll be right back". Came back to the counter with a brand spankin' new iPad 64-3g. Pulled it out of the box, turned it on, activated with my SIM from my old iPad, erased the broken one...out the store, less than 5 minutes.
Just saying! There are going to be bad apples (pardon the pun). But Apple's support and exchange policy is second to none.
IMVHO, and other than the new Nexus (I'm brand agnostic and have owned several Android phones and tabs), there is NOT a 'Droid phone that can keep up (battery wise--everything other argument aside) with any of the same generation iPhones. It's one thing Apple has done absolutely RIGHT on these little guys!!! They last ALL day
I was so paranoid buying the iP4s that I bought the Mophie case (w/battery) as a contingency plan...NEVER have I had to use it in the month and a half I've owned it! And I use my iPhone constantly! ALL DAY!!!
Sorry...didn't mean to ramble. But I think (as many, well respected reviewers and Droid owners) that you maybe got Very VERY lucky with your "S2's" battery life

It's not that way for most of us!
J