Sienna Mercato has really great specials for happy hour! They also serve a poutine that is on par with some places in Toronto. I'm also impressed by their selection of draft beers -- I was excited to find that they sometimes feature the watermelon beer from 21st Amendment.
The meatballs, however, are a bit dry and poorly seasoned. They are also soaked in sauces that taste excessively sour and sweet. In fact, it is often hard to discern one type of meatball from another. I've tried their meatballs in a salad, on a sandwich, or by themselves and I can't say that I look forward to eating them.
Although it's a great place to grab a drink in downtown, I wouldn't recommend having a meal here.