I went for a run through here on my recent trip to Montreal. I was staying close by, so I also ran the 5 blocks to/from the park. It has plenty of paths and sidewalks, as well as a large pond and fountain. There's a decently sized hill and a small wooded area you can run through. There are also tennis courts, basketball courts, a hockey rink, soccer fields, a baseball field, and lots of grassy areas for laying out in the sun. There was also a swimming pool, but it was closed :(
I thoroughly enjoyed my run through here, despite its brevity.