Which ROM is the best depends on what you want or like.
I am running CM 7.2 which is a battery killer for some reason.
Before I was using CM 7.1 which the battery would last all day but there is no offline charging.
Those are the only two I have tried. Talk, text, web, wifi... work on both.
There should be a stable release of ICS for the Optimus One/T soon, something else to look in to.
Anyway just give it a try if you don't like it restore the backup...be sure you make a backup.
As a side note if you try to follow the sticky at the top of this thread to root/backup/rom without touching a computer, you will quickly find out it is out of date and some of the links don't work.