Mine was definitely new. Other than not getting a warranty card I'm very happy. I've done test shots to compare it with my 28-135mm IS and I can already tell this lens is sharper. My 28-135mm was always soft for me so I'm not shocked.
I'm keeping mine. For $750, there is no reason to go buy new from B&H to get a 1 year warranty. I've had 4 Canon lenses, 3 SLRs in my life and I've never had to warranty repair any of them...