Need more time before I'd ever be able to really compare ... this is a monster of an album though, IMO. If you look at them objectively, I'd probably go with this ... and if I continue to develop an emotional connection to this album (which is why I love 59 so much) there's a damn good chance it passes it. That's what remains to see where they end up I think ... cause the personal connection so many people have with 59 Sound makes it hard to ever truly "surpass" in a sense.
As I listen to Sink or Swim on the bus right now here's a question for you: what are the odds Gaslight plays at least one show where they play SoS front to back for the 10 year anniversary in a few years. I'd pay several hundred dollars for a ticket.