Some friends and I booked Cycle Tours Montreal on the first day of our visit as a way to get a feel for the city. We totally scored because this was a fantastic ride and gave us such a great baseline for the rest of our trip!
The owner/guide, Shea, was extremely knowledgeable about the city (when we rode to the top of the mountain he could point out the major buildings and give fun facts about them) but struck a great balance between straight tourist-ness and neighborhood coziness so that we didn't feel like outsiders but part of the Montreal family.
It was a comfortable ride--you can get your spin on in some parts if you want but you can also just cruise if that's what you're looking for. Highly recommend!