Versus Sybase!? Not my experience (but its so long ago now). I feel this may be a just a comfort-zone switch for you. Like, Sybase is known and therefore already figured out and "better". All big systems take some ramp-up / comfort-building time. As others have said, the documentation, the community (still on IRC and email!) are excellent. And heck, digging in the code for information is not so terrible either (and it's huge, and C (and I don't do either of those things) and I still found what I needed). I'm sure you'll be used to it in short order. I've already poured you some Kool-Aid :)

I found the o'Reilly book, Postgres: Up and Running approachable if you have some db experience.