Old ECW. It had a better feel, better matches, less nonsense, and great talent. WWECW has some good talent, for instance CM Punk, Matt Striker, RVD, etc., however the ones getting the main event push are your Tests, Lashley's, and Holly's, which is a shame and a waste in my opinion.
Take an event like D2D 2006, and compare it to something like November to Remember 1996, and you have a clear difference in quality. N2R provided you with classic matches, such as RVD & Sabu vs. The Eliminators, while D2D offers you a squash between Tommy Dreamer and Daivari.
Old ECW > WWECW.