I'm no doom connoisseur, but this seems rather atypical for the genre. I only say that because I usually find most doom uneventful. Then again I don't have adequate knowledge of the genre to back that up. While calling it groovy might be pushing it, it certainly has head-bob worthy riffs and drum beats, laced with tasty melody for a cherry on top.
After two back-to-back listens, I can firmly state that this is anything unlike III. This is more doomy in its own right and has a totally different vibe to it than the last one which was very highly spacey and almost blackish. Though I hear that brilliant motif from the last record 17.50 mins into this. In the end I won't rate it as highly as the last one. But it still is one of the great doom albums of this year. And distinctively Monolithe-y in its own right. So, darn good I say.
One thing to love in this album are the amazing choruses. Reminds of that scene from the 2001: A Space Odyssey movie where the chaotic chorus starts to pick up when anything goes near that black monolith.