The book is a masterpiece. The made for TV two part miniseries was ok, but there is something about viewing somebody else's vision of this type of story that isn't as satisfying as creating your own vision while reading the book. What's terrifying for one person is laughable to another. When I saw the ending of the TV version I was extremely disappointed because the vision I had in my head was more terrifying that what I was viewing.
Tim Curry's Pennywise was more disturbing to me because most of the time he looked like a real clown...sort of. This current Pennywise is entirely monstrous, as shown in the clip. It's hard to tell from just that much. We'll see.