This album came after "Astral Weeks", regarded by many as Van the Man's best, but I find "Moondance" every bit as good, in fact more enjoyable to listen to. It has a timeless quality about, and it really doesn't sound like it's 30 years old.
Overall, it has an American feel to it - the first song, "And it stoned me", reminds me a lot of The Band, and the brass, which is used throughout, sounds a lot like Springsteen / Southside Johnny / The Blues Brothers.
The album has a very soulful vibe. On a couple of the songs there's even a gospel flavour. ("Come running" and "Crazy love") Then there's the swing tempo on "These dreams of you", and the slightly jazzy title track. "Everyone" has a more English (though perhaps I should say Irish, as Morrison's Irish) sound, with folky instrumentation, even a flute.
It all makes for a varied listen, but it all gels together really well. Morrsion's voice is extremely passionate. When he sings "I want to rock your gypsy soul" in "Into the mystic" he makes it sound like there's nothing more important in the world. The album has a romantic, feel-good kind of atmosphere - it's good late night music.
Favourite moment on the whole album: "Turn it up? Turn it up? a little bit higher" (in "Caravan").

If you prefer Van Morrison when he was recording songs like "Brown Eyed girl" and singing with Them, then you should love "Moondance", but I can't see anyone else being disappointed by it. Anyone who doesn't like it must have no soul.