If I had a choice I'd go burl just on the uniqueness factor and the psychedelic vibe. I like birdseye for that reason too but never saw a PRS or any other electric made out of it that looked decent, maybe not enough custom pieces out there or produced. The spalted stuff is cool like that too but most of the ones I've seen only have natural finish, so I haven't seen enough in stained finishes to form an opinion.
To be honest, if I really had the choice I wouldn't even go maple, I've seen so many stunning pieces in woods like rosewood, ebony, zebra wood, and koa, that I'd go for something "one of a kind". Naturally that would open the door for a bit of research on tone woods because looks and uniqueness is fine, but tone is king.