Hi,
I publish with Orca and think they're terrific. They have a good website (orcabook.com) with lots of information about the company, their submission guidelines and their books.
They promote their books well, including in the school system (advertising, catalogues, teacher's guides etc) and have sales reps in both Canada and the US. They have a US office and warehouse in Washington and distribute their books on both sides of the border.
Orca puts out about 60 titles a year I think, from picture books to YA, which actually makes them one of Canada's largest publishers of kids' book. I'm pretty new to all this but I have heard only good things about them from other authors too.
Hope that helps!