I've had a X since it's release in the UK. at first I was shocked at how fast my battery was dying, but then after 2-3 days I released I hadn't set the screen brightness to automatic... wow what a difference that made to the battery.
With ICS you can go into settings --> power option and there is a menu item that shows you the applications using the most power, almost always the screen is at top, but for my first 2-3 days it was using up 85% of the battery juice compared to all other apps. Now it's much less.
I can happily watch a movie from netflix streaming over 3G, and still have plenty of power left by the end of the movie. I do maintain a power cable at home and work now however just to keep it topped up.
One thing that does bug me, is certain pre-installed software that looks to be fixed within the system and if you try to uninstall it tells you that it'll uninstall all the phone updates! I don't use facebook, I never will, and I don't want some autotrader software on my phone, but I can not remove these. I might need to install some clever app to do it for me but what a hassle!
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