Okay, so the menu is spectacular. I've had things here that I never though could be done with chocolate. From hot chocolates to ice cream to more elaborate deserts, I've yet to try something here I didn't like.
However, it is (unsurprisingly) very busy, and wait-times for a table can be long. So while it would be a great date spot *in theory*, something gets lost in translation by the time you get a table and finally get served.
I wouldn't do it on a first date, but it might be a fun place to end a night with someone you know well, especially after dinner.