I go to YUL quite frequently. I have had great success with Priceline staying at absolutely fantastic hotels for a fraction of the regular price (gees, I sound like an ad).

The hotels I have gotten include:

Bonaventure Hilton - good
Loews Vogue - excellent
Omni Mont Royal - great
Hotel Sofitel - my personal favorite

These are all 4* hotels and the highest category that Priceline offers for YUL.

Never been burned, and the prices usually ranged between $75 and $105 USD per night. You will not be disappointed in any of these hotels.