I'm using OOo 1.1.1 for about 50% of my day to day work.
I have successfully converted several spreadsheets from Excel to OOo and currently use the Text application to write the notes for the Open University course I'm doing, though I don't yet trust it enough to send electronic assignments to my tutor as there is requirement for them to be word 97 compatible.
I like the built-in PDF converter (M$ take note) but am missing the print a label/enveloppe from an address feature (it can do but not as smoothly as M$'s). Like Mac said it's not quite all there but they're working on it.
I look forward to version 2 when hopefully I can kiss M$ goodbye...!
amofw