It depends on if you ask me as player or as DM
As a player, I only played the WotC Adventure path modules (till Iron fortess..).
From all adventure path modules I played the best adventure
IMHO as player is: Speakers of the dreams
IMHO as DM it would be Nightfang spire, because I really love the two golems and the scrying device. This is evil

, but as player I would hate that
I and my players hate dungeon adventures, dungeon crawls or hack ´n slash adventures.
I love adventures of intrigues.
So far I only own some non-WotC adventures, but most of them also are dungeon crawls in some kind
Just my 2 cents
yennico