While I LOVE the album...I think coining it a masterpiece would be pushing it. A masterpiece to me is an album like Born To Run, London Calling, Revolver, Blonde on Blonde, Pet Sounds, etc.
I DO think that Elsie was drastically unrecognized and underappreciated though. To me, it's one of the most cohesive albums I've heard for quite a while and really cements Brian's placement as one of the top rock n roll songwriters today.