I'll watch the series no matter who does it or where. I'm not a purist or a fanboy for Sandman -- I like it, and I'll compare the books to the show (just as I do for True Blood and Smallville). I think putting it on a pay-cable network is an awesome idea because it'll allow the producers to make it more faithful to the books -- language, violence, nudity, and thematic elements don't have to be restricted. And can you just imagine how scary it'll be the first time the Corinthian takes off his sunglasses? Just as long as the producers simultaneously release it in other ways (such as iTunes and Netflix), because really, by the time this comes out too few people will have cable.
And of course I want Gaiman's involvement -- and I think Eric Kripke would make a great showrunner for it as well.
But if it gets bad reviews, or people are saying "this is against the spirit of Sandman, even though it keeps the ideas", I'll still watch it. Because it'll still probably be pretty cool.