WCW by far. I enjoyed watching WCW back when it was simply Jim Crockett Promotions. During much of the 80s, in my opinion, it had an overall better in-ring product than WWE. Even during the lousy years of WCW, which was during the late 80s through much of the early 90s, they still had great wrestlers on the roster. For me personally, and probably for a lot of others, when I think of WCW, I generally think of most of the 80s and the mid to late 90s as far as the prime stuff, at least for my lifetime, in the company's history.
For the most part, I simply wasn't a fan of ECW once I saw how much of a one trick pony it was. I know some will try their best to convince others that there was more to ECW than the hardcore matches but, I don't really see it. Even former ECW wrestlers have made that claim, yet whenever you see a vignette about ECW, it's always about showing clips from hardcore matches & the extreme violence that went with them. When TNA did the Hardcore Justice thing a few years back as an ECW tribute show, which it will be again now that the Hardcore Justice is part of the One Night Only ppv concept, it was, again, all about the hardcore matches. When I look at most of the ECW roster, I don't really see a company that had very many genuinely good wrestlers. They had some, no doubt, but, in my eyes, most of the roster was made up of wrestlers who made full use of the over the top violence in ECW matches to cover up their actual lack of pro wrestling ability. I wouldn't take 20 companies just like ECW for 1 WCW.