As the OP, I must say my battery life has stabilized and improved. On this replacement, or SECOND 4S phone, after a couple drain-to-below 20% and then full cycle charges, I said %#^! it, and decided to treat the 4S as I had my 4. I'm leaving wifi on, bluetooth on (so my truck finds it), and cellular data (3G) on all weekend, notifications and Siri on, mail fetching every 30 mins, with 5 mail accounts. Last weekend I used my phone normally, with all the aforementioned items running in the background, brightness at 50% or so, notifications on, Siri on, and I ended the day at or above 40% each day with my usual light to moderate use (playing with the phone on honeymoon period is winding down). In fact, Friday night I intended to do a full drain and charge, so I sat up in bed watching episodes on tv.com to drain it since 6:30 am to 9:30 pm and I was still at over 40%. This is better than I require.
Here at work in my interior high rise office I don't have wifi or the need for bluetooth, so I've turned wifi and bluetooth off, and even cell data since I know I have poor 3G reception. as of 10ish this morning, 5 hours off charger, I'm at 97% with a couple weather checks, one email and one text sent, update posted on my "Loseit" app....
I had restored--nervously--from the backup of my FIRST 4S, which had serious standby battery drain. I really think the battery needs to be treated how you intend to use it and to go through some deep cycle drains and recharges. At least for me, it seems even this SECOND device started out poorer and has stabilized somewhat. Is it as good as my 4 was? No. Maybe I'll end the day at 40% whereas I could end at 65% with my 4. I feel comfortable enough now that I gave my 4 to my stepson to take back to college this weekend.