@tobyyoda: Thanks for a useful observation regarding advanced WiFi setting. However, for me it is one of the key functions of a smartphone to have email syncing over internet constantly on (even in sleep mode).
My further observations for the full "usual" day on ICS 4.0.4: I noticed that the "Exchange Services" grabbed a large share of battery use (around 25%) as I had wifi or 3G turned on for most of the day and it was mostly used for syncing several email accounts. It's a bit on the high side IMHO, given no intensive use of the internet, just email syncing without attachments and a few widgets e.g. Bloomberg etc. updating. Android OS battery use stabilized around 20%. Screen (and I do not use live wallpaper) used around 30% of the battery leading me to suspicion that auto-brightness still does not work perfectly (although visually it looks notably better than on 4.0.3). Overall my phone lasted a bit more than 12 hours on the full charge (with wifi/3G on for most of the day) vs 6-9 hours on a comparable day with 4.0.3. Thus I conclude that the improvement is notable, but there are still places to work on.