I use MS Office XP at work but have OO on my personal "XP home" based laptop as well as on this Desktop which is running SUSE 9.
I regularly work form home using OO to creat and edit docs for work with no problems (Well the way Office converts OO highlighting is odd but I know how to remove it in word now!)
There are minior differences between Office and OO but I'd say no worse than between versions of Office.
Personally I like the auto complete in OO it's very intelligent.
And amanoffewwords Open Office will always be free, it has to be by the terms of it's licence agreement. However you can buy it with professional support from Sun as Staroffice.