"Intuitive, elegant office suite"4.5 starson by edgedesign
Pros: Easier to create more professional looking documents/presentations
Cons: Numbers lacks features found in Excel (but many won't need)
Summary: Pages is much better than Word. Numbers is more intuitive than Excel. Keynote absolutely buries Powerpoint.
That said, there are some features you might find in MS Office that you cannot find in iWork, but the ease-of-use and other advantages outweigh the missing tools that most people never even use.
Pages is both a word processor (a la Word) AND a page layout program (a la Quark or InDesign). The pro layout apps can do much more, but Pages will suffice for most small businesses and individuals.
Numbers is more flexible than Excels 'grid' and uses plain English for formulas. Tables, charts and graphs are clean and elegant.
Keynote is the star of the show in my opinion. Simply compare any Keynote presentation to a Powerpoint presentation and you'll see why. There are many professional looking effects and templates.
WARNING: Long time MS Office users will need to clear their minds before working with iWork. The interface and methods are significantly different than Office. I believe most will find iWork more intuitive and better organized, but you need to leave your MS baggage behind or you may become frustrated.