One of the best SEO resource websites out there.
My complaints are that many SEO tools that you can find for free elsewhere on the Internet are not available for free use on seomoz, on their resource page Internet Marketing Handbook, even though they call it a "free resource page". It's only for paying members, even simple tools like checking keywords and other things. Definitely not impressed with that.
Even so, probably the main reason I love this site is their articles, community and blog. I've used their tools before, and my money is best spent elsewhere. Their tools aren't bad, but they aren't worth it for the price in my opinion.