My situation doesn't fit your question very well - almost all of my writing can be handled by a good text editor that accepts unicode, so I rarely need a word processor. And it's done at home at a desk with a browser open to a half-dozen windows, so I'm on my general-purpose computer.
Now technically, for the past year that's been a 10" Windows tablet, but I had it docked with a keyboard and mouse and a wired connection to the net. So, it's hardly what comes to mind when thinking about tablets.
Occasionally, even when I don't need to produce sophisiticated formatting myself, I've needed something more upscale than a text editor. It usually has to do with searching for patterns ... paragraphs preceded by two or more blank lines and starting with a numeral, for example.
MS Word has usually worked well for me in these cases, but there have been times when I was on a linux machine. Open Office Writer was almost as good (but not quite). Both of these applications sorta rule out Android.
(The solution, of course, was to fire up Vi Improved and make glorious use of regex pattern matching.)
Convenient cut-and-paste is also a major requirement. I do a lot of it, especially between browser windows and documents.
I also use spreadsheets halfway often, almost exclusively for my own study and entertainment. Here, the larger the screen, the better the usability. I haven't done anything in tablet format, but I recall the difficulty of just reading the darned things on PDAs. Anyway, for this, Open Office Calc satisfies my needs pretty well, even when opening other people's Excel worksheets.
-- Ed