I have updated my 2011 Xperia to ICS a day before.
The phone runs smooth and suprisingly faster.
Good UI and very efficient.
HD videos play without any lags.
No issues launching Caller.
I have noticed that the contact images which were used to be half of the screen before are now thumbnail type.
This is a problem to me. 
Please let me know if there is any solution. I dont want to use any 3rd party app.
Thanks in adv for your advice.
[build (4.1.B.0.857)]