Since this is an often-asked question for switchers, I'll share my experience with Office suites on my Macbook Pro with Intel Duo 4GB Ram running 10.5.7.
I've gone back and forth. I currently have installed MS Office 2008, NeoOffice 3, and iWork 09.
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Office 2008 opens the slowww-est of the 3 and can't open any macros contained in Excel sheets I email from my Windows counterpart at work. I have suspicion as to why the macros were taken out, but it's my conspiracy theory at best. M$ says they'll return the macros with the next Mac version of Office due in 2012-ish. Entourage 2008 is NOT a feature-for-feature match Outlook-clone and doesn't direct sync with iPhone.has to use iCal as a conduit and that is marginal at best. Forget integration with Google.
So far, the M$ Office 2008 software has had more support patches than any other software installed on my Mac. Regrettably, I have to open Word docs sent from my Windows work computer and even then, formatting doesn't stay the same. What's up with that?
Bottom line is, I don't appreciate giving M$ the $150 for this clunky software. I've read other user recommend using MS Office 2004 for Mac since it does include the macro support for Excel.
NeoOffice 3 is a free derivative of the free OpenOffice 3 that was recently released and often has enhancements not found in OO3. NeoOffice has found a home in the Dock as I use it alot for home-base quick document or spreadsheet use. I like being able to create any type of document without having to open another program and can save my work in a default MS file-type(.docx, .xlsx, .doc) in case I need to email it to the office. I haven't tried the Presentation piece of this suite. There isn't an email client included in this Office suite.
Bottomline is, NeoOffice is a great piece of software and the free price tag shouldn't negate it's value. It's cross-compatible with M$ Office and adds a few tweaks that make it more Mac-friendly.
iWork 09 was recently purchased as part of the Mac Box set mainly because I wanted OSX 10.5.6(with all the updates) and iLife09 and it was cheaper to buy it this way. While I haven't tried out the more intense parts of iLife09, it shows great promise as I find myself using it more. You can export your documents into Word and it hits/misses being 100% perfectly imported into Word. I like the media integration and the ease of use of dragging and dropping, which is a core strength in Mac software altogether. I was up and running with Pages alot quicker than I had with Word or even the dreaded Word 2007 with its changed interface.another personal UGH! for me.
Bottomline here is, $79 is a great price for a suite that includes Pages(Word), Numbers(Excel), and KeyNote(PowerPoint) and integrated well with the Mac media suites. Apple seems committed to continue making iWork a viable work suite. I'm hopeful one day that Apple will merge iCal and Mail together so it can be an Outlook killer.
Overall, this one is a toughie. Most worksites use M$ Office and depending on how much work you want to put in so you can keep using an alternative, I'd recommend a combo of NeoOffice 3 and iWork. Heck, sometimes the Mac Office .doc and Windows Office .doc files don't import and display exactly anyway, so I would save the $150 and spend the $79 on iWork and add the free NeoOffice. Use Pages for your word processing and NeoOffice Spreadsheet for excel-type needs.
If you're just getting starting and on a budget(ahem, college students), NeoOffice is the way to go. Just plan to get iWork at some point.
As a 'I have to say this'..if you have to work intensively with Word or Excel from the office and at home/on the road, then bite the big bullet and purchase a copy of Windows XP, Office 2007, Parallels 4.0 and install them. Not the most desirable option since it runs between $400-$800 to do this(depending on the version of Office08 you get), but it may be necessary if it's work-required. Or, choose to not do work at home. ;D
MS Office 2008 (30 Day Trial Available) Mactopia - Discover Office 2008 for Mac from Microsoft
NeoOffice 3 NeoOffice Home
OpenOffice 3 OpenOffice.org - The Free and Open Productivity Suite
iWork09 (30 Day Trial Available) Apple - iWork - Documents, spreadsheets, and presentations. The Mac way.
I hope this helps. Sure would appreciate feedback if I've mis-quoted something here. Let us hear your experiences and recommendations!