There is not a single Vonnegut book I don't like. Sirens is one of those that's him at his "trippiest", for lack of a better work. The story is secondary to the concepts when he's doing that side of his stuff, like in breakfast of champions and timequake
But it manages to be a good story anyway, which is why I love Vonnegut. His self character, Kilgore Trout is a caricature of himself as he sees himself, where he thinks he comes to with great ideas and then fumbles them at least a little. But it's more the opposite, where he comes to with some wacky ideas, but uses his gentle touch on things to make them work well.
It isn't my favorite, I can't pretend otherwise, but it is a great read