A "Power User" is one who, for example, has thirty macros in a spreadsheet, with a lot of formatting and linking between sheets; OO.o does not support pivot tables or Word macros, however, and its PowerPoint clone has some compatibility problems.
Another word might be "professional." I am a fairly sophisticated user (one level below "professional" and I have never had a problem with interoperability in word processing or fairly complex spreadsheets. Most users would have absolutely no problem with compatibility between OO.o and MS Office.
OO.o will open all Office files types, and almost all versions of them. You can also use OO.o to create a document, and save it as a MS .doc that a Windows Office user can open. Transitioning from MS to OO.o should not be a major problem, either, as the layout and functionality are quite similar.
As a bonus, you get modules similar to Visio and to Access thrown in.
Edited by jgweed, 11 March 2006 - 03:53 PM.