I've always loved loved loved Demetres! Ever since my high school days!
You have a crazy selection of desserts so it's great depending on how hungry you or how much of a sweet tooth you've got. You can get something as complex as ice cream with crepes/waffles with brownie pieces and syrup or something as simple as a milkshake.
Personal history: I've previously tried the Tongue Depressor (from what I can remember, it's basically all the goodness I previously mentioned but it is pretty big so prepare your stomach), Nutella milkshake (yummy) and One Smart Cookie (I think that's the name! Basically chocolate/Nutella ice cream sandwiched between two chocolate chip cookies and resting on Nutella spread....SO good!
The service is usually very quick but it can depend on how busy they are. When I had the cookie, they were pretty busy so I waited quite a bit for my dessert but overall, I'd say their timing is pretty reasonable.
It's a good sized venue so you've got tables and chairs or booths and the interior design is quite lovely. One thing I absolutely love about them is their creativity with naming their desserts! Take a trip there and see for yourself :)
Definitely recommend!