The exhibits in le Musée des Beaux-Arts de Montréal can be quite hit-or-miss, but there's a lot to see and the price is low, so I'd recommend paying it a visit.
The museum is actually multiple buildings, all connected underground. Once ticket gets you access to them all (except there's a special exhibit which costs extra, if you want to see it too). I'd recommend starting with the permanent collections, then deciding later if you want to upgrade to see the special exhibit.
Personally, I found many of the exhibits quite uninteresting. There's a lot of floor space dedicated to contemporary art and design (such as lamps and chairs and vases and bicycles), and not as much classic art (i.e. paintings and sculptures) as I'd prefer. However, if you're willing to wade through it all (or if you know where to look), you'll be rewarded with some beautiful pieces. The best collection in my opinion is in the "Peace Pavilion" in the main building. This was mostly Greek, Roman, and Renaissance art. There were also some nice rooms in the other buildings, but they were fewer and further between.
The best part was that it's free if you're 30 or under! So the pockets of nice art plus the great price made it overall a worthwhile experience. Check it out yourself, if it sounds interesting to you.