I've been using Open Office since version 1, when it was a bit of a clunker, but free. The up-to-date version has had the rough edges removed, and for my purposes MSo has nothing to add in the way of improved facilities that I need, but does have a heck of a lot of "cool" (Bill Gates' word) extras that I would likely never find a use for. Memory salesmen like the extra facilities.
OO can save and read MSo format files. I'm not sure about going the other way. Microsoft prefers its own standards to industry standards, arguing that as the largest supplier, it is the "standard".
Imported documents appear the same as the original more often reading them with OO than with MS Office readers. My most commonly used spreadsheet programs started life as Micro Office documents on my PCW, have been ported through Lotus 123 when I got a PC, and have wound up as OO files. A foray into Excel on the PC at work messed up the cell formatting, but that was a while back and MS might have sorted it. Or not, as the case may be. I used Woks for a while, but the versions of Word and Excel had their basic abilities just too cut down for even my limited uses, and I wound up using OO anyway.
My preference is to use the freebie, and spend the savings on something worthwhile.
Of course, if you install Linux, OO is part of the deal.
