Having had to adjust to Vista and Windows 7, I don't feel too bold in saying that switching from Windows to Linux with Gnome 2 or Gnome 3 wouldn't be a stretch for anyone. Windows typically frustrates me, the new Office Ribbon whatever crap is HORRIBLE, etc.
I keep seeing this, yet I haven't personally experienced this frustration (and I use the hell out of Excel every day.) Initially, yes, I was annoyed that I couldn't find what I was looking for within the menus. Then I noticed by accident that 99% of the old (i.e. 2003) keyboard shortcuts still work -- they're just not advertised. Alt+E+S still brings up Paste Special, Alt+D+F+F still applies auto-filter, Alt+I+W still inserts a new worksheet, &c. The only real frustration I've had is that some of my macros needed some QA during the conversion and pasting pictures of graphs into PowerPoint is pretty ugly.
I can't comment on Word because we don't really use it in my office, but I'd gladly gain the extra functionality in Excel (multi-threading (huge win for me!), data sets greater than 65K rows, increased memory limits, the list goes on) for the little bit of frustration that I've experienced.