Since the city of Montreal gets its name from this hill overlooking the city, I knew that I had to make at least one trip there. I finally got my chance the last day of my trip when a colleague and I took a trip up there for the Tam Tams festival.
It was a lovely park, reminding me of Central Park in NYC or Hyde Park in London but with this also comes the feeling that its maybe a bit too big. I personally found Parc Lafontaine (http://www.yelp.ca/biz/parc-lafontaine-montreal#hrid:GkpcFFOGciTvY2BAun3ajQ) to be more my style urban park - a bit smaller, a bit more landscaped, and a bit more home-like.
We had problems finding places to sit because it was so popular that most of the benches were taken! We realize that the smart folks brought blankets with them so I'd suggest that if you're heading here, bring something to sit on if you're planning on resting your legs.
But you still must come here if you're visiting Montreal! There are beautiful views of the city and you realize why the city was founded after such a beautiful place.