I ate at Diwan during Winterlicious, so my experience with the restaurant itself is limited to their set menu options. I came in not knowing what to expect from a Mark McEwan restaurant, but at the same time I know he's actually not in the back cooking for us :(.
It took us a little while to get seated - perhaps OpenTable had something to do with the confused looks from the Front of House staff. Regardless, they were really welcoming. The restaurant is bright and spacious and the decor really sets the tone for the food.
The food itself was good, but I didn't find myself dying to come back every day. Writing this review several months later, I can only vaguely remember the dishes I had. A blended soup which I thought was just okay, a Chicken Biryani which was good, and the carrot cake (or at least I think it was a carrot cake) which I think was left out a little too long.
Granted, this was a Winterlicious setting, so it does warrant another try on regular day. I enjoyed the experience overall though and would try again.