lots of Muse reviews here
Basically, if you're a web/graphics designer, as opposed to a coder, and you're not concerned about code quality and efficiency, then you'll probably like Muse.
If you're an experienced coder and you know what you are doing regarding being standards compliant, then you probably won't touch Muse or most of the other wysiwyg type editors.
Not necessarily. Have a look at Dreamweaver.