ECW is already the best wrestling on TV, that would make it even better. I've never even seen the guy wrestle so I'm excited to see him. SD! might be "ok" for him too, just as long as he doesn't go to Raw...that'd be worst case scenario. Though I can see Hunter getting Vince to put the worlds best wrestler on his show so he can bury him.
Going to ECW first definately benefitted CM Punk, Evan Bourne, Kofi Kingston, Jack Swagger, Hart Dynasty, and others. It's also where Miz & Morrison grew as performers. It allows these guys to be built up the right way...vs. jobbers, then get wins over mid carders, then work in top of the card matches for the ECW title & such. If you dont get over, its because you don't deserve to get over, like Chris Harris or DJ Gabriel.
RAW is a death sentance where nobody ever gets a real push, and it's the more entertainment based show. You are swimming with sharks on the show, with the likes of HHH, HBK, Orton, etc killing careers left & right.
SD has a good mix of talent, and Michael Hayes does a good job with the booking, but its on a dead network.
As i've said before, Danielson will have to drastically change up what he does to make this work. He's the best "long match" worker of this era, but he has to be able to adjust to 5-12 minute matches. He's really, really good, but it will be hard for this generic looking, pasty, normal looking white dude to get over to fans conditioned to only accept super hero looking steroid freaks as stars. He has charisma, but it's the type of charisma that comes through his work, similar to Chris Benoit or Ricky Steamboat (before he roided up). He wouldnt even stand out at your company christmas party, let alone in a locker room next to Batista or John Morrison.