Personally I have two gripes with iWork.For me, iWork is perfect for what I want, and I like the way it stays simple. Office allows for much more complex editing to be done but I don't really need that. The only thing I hate with Pages is that when you insert and image and make it "inline" and not "floating" so that it moves with your text, it becomes completely buggy, unpredictable and total nonsense. If anyone has tried placing images in a Pages, they know what I mean. Maybe I'll give Office a try just for that reason.
One is that Numbers doesn't have nifty Sheet tabs at the bottom, instead Sheets end up in some weird nested tree in the left column and it not only looks crappy but it's also a sluggish manner of navigation with twice the number of clicks.
The other is that Office on Windows allows you to paste Excel stuff into Word (and vice versa), so you can do stuff like create an nice invoice template in Word and then create a table in the middle of it that's all Excel. When you double-click on the table you launch a kind of mini-Excel inside Word.
If you load such a document into Pages, it turns the Excel table part into a non-editable bitmap(!) where it gets everything wrong (fonts, font sizes, column widths etc). Useless. Office for Mac doesn't handle it as well as the Windows version, there's no "mini-Excel" inside Word, instead double-clicking on the table launches Excel and lets you edit the table there, and when you close Excel the table pops back into the Word doc.
Since MS introduced the OLE technology (which is what allows linking and embedding between documents made in different apps) in 1990, you'd think Apple would have similar technology by now, but if they do, they're sure not using it for iWork.