I've been using Sitebulb during the beta period, and found it really useful for any projects involving SEO, whether that's doing a quick overview and check, or a full website audit.
I've used most of the competitors, and it seems to be the best yet for being able to run a full website crawl and analysis in a way that's easy to understand and share. Which means I can easily use it to demonstrate to clients without having to explain reams of spreadsheets (which is nice).
Crawled urls by depth is a really nice addition to help locate bottlenecks with navigation and internal linking