It probably depends on what you are looking for. I tried using Entourage because I like the idea of having tasks, calendar, email, and contacts all integrated, but I quickly ditched it because you can't subscribe to remote calendars. That makes it useless to me.
Email vs email, I can't say because I didn't use Entourage enough, but I can sing the praises of Apple mail. Works well, super fast search of 20,000+ messages using Spotlight, data detectors that work with iCal and Address Book, etc. It has an annoying bug that has lasted for years where it likes to create a bunch of nested inboxes if you store deleted mail on the server, but most people don't need to do that, anyway.