Angel and I reviewed Maison Kayser when it opened in NYC, and we loved it. We went back to the original, though there are now three other locations, and we still love it.
Angel still loved the mousse. She still loved it more than I did, but I liked it a bit more the second time around. I think I let her deal with most of those brownie bit things on top this time.
The tart, though, was steller. Perhaps a bit too much crust -- as is often the case with mini-tarts -- but that is easily ignored. It's an intensely chocolatey experience.
Bottom Line: This place is really great, and everyone should go there. Period.