I've started using AbiWord as an alternative to open office on the old ppc imac I have running linux and I'm quietly impressed at its capabilities as a lightweight word processor on an older slower machine.
It works, it's reponsive, it's fast and it can export in a lot of formats - what more can one need, and yet it's a fully featured word processor.
Apart from the help key on the mac keyboard becoming the insert/overwrite toggle I've come across no real idiosyncracies.
With open source - everyone focuses on OpenOffice as a Microsoft Office killer. AbiWord gets ignored, but actually it has all the functionality 90% of the popukace need yet it needs a much less meatier machine - ideal for small low powerd nano portables.