You clearly haven't used Office in a while. Since Office 2007 Microsoft have used the Open XML format, meaning a document created in Office 2013 can be opened in 2007 or 2010 easily. And if you have Office 2000, XP or 2003, you can install the open XML converter for full compatibility too. And this is for BOTH Windows and Mac versions.
I'm not even going to start what amazing tools Office has over iWork. It isn't just proofing tools. Word is miles better than Pages for handling and organising larger documents (since I spend my life in a word processor, I know this stuff) and Excel is undoubtedly much better than Numbers. If you want powerful features, Office is certainly still the best tool.
As for Windows 8... people are only complaining because its different. Once you get used to it, you realise its actually a lot better than previous versions.
I'm clearly using Office daily (2013 I think this computer is using) but I use it as a normal user, like .docx documents and none of the "you can find those options online r in the advanced menu) it's not my primary tool, but I use it daily.
I sit in a large company where everyone have office as a standard install, and most users will, as me, be regular users, but not advanced.
and it's organizations like this that keeps office alive. as a normal user office is as I described, it's annoying they are changing formats, annoying they are changing the UI constantly, when all I wanna do is make a bullet list in document or something small.
if we had an alternative, I woul've used that. and I think for the 5000+ other users feel the same, only few programmers and engineers actually use spreadsheets and word macros fully.
then MS removed VBA programming for one or two versions...it's back now...but macros are not yet functioning in Windows 7 (from XP).
in general MS is screwing over their regular users and the powerusers with each update.
I agree Winodws 8 is a nice OS, it's quick etc. but when you speak to people there is so much frustration from new Windows 8 users, this is what I reflect on in my post. personally I think 8 is pretty good.