Or would it be more accurate to say that nobody is saying much because, despite Neil Gaiman's involvement, it wasn't an especially good episode, and nobody wants to be the first to say that?
In that case, let me relieve you of this burden. It was okay-ish. Just really nothing very special, and not a patch on e.g. The Doctor's Wife, so a little disappointing to those of us expecting the usual Gaiman magic.
Don't get me wrong, if you haven't already seen it, it's as worth seeing as any other average episode. But Gaiman has done much better, and so has Doctor Who.
There will probably be spoilers in any comments.