Some other things to consider that no one mentioned yet:
It's shorter, and you're not schlepping between seven rooms in the dark. You have one well-lot physical room, but it's broken up into four virtual rooms for "one-per-room" effects.
The combats have embedded thinking puzzles. Last year, characters sometimes had brain-swaps. There was a way to swap back.
There are more tactics than a typical one-board combat. Maybe the super-tank should battle one monster solo while everyone else gangs up on the other two. Maybe that's a bad idea. Don't send the tank against a horde of cultists, let the AoE wizards do that... But it's more interesting than everyone sliding at one critter.
The Horns of Gondor are heartless, making you stand around bored after the monster is dead, or declaring you defeated because your time ran out. Neither happens in Grind. Kill one, then move on to a new one, or help your team with theirs before another wave appears. If you're used to the frustrations standing around bored, or trying to squeeze in one more combat before the cymbals, you probably won't miss them.
IMO, some of the best completion tokens have been from Grind. Horn of Blasting, Flask of Sharing, FOP: Spider - all Grind. Sometimes they're suboptimal, but the same can be said of the normal dungeons. Lamps were awesome, though...
Full disclosure: I'm one of Eric's minions so I'm a bit biased. But I have a ton of fun DMing it, and it sells out fast every year, so... there's that.
"Ceci n'est pas une pipe" - Magritte