Stu gave you good advice on Le Centre Sheraton, it is well located. If you bid on Priceline 4 stars on the City Center zone the hotels are the Sheraton, the Hilton Bonaventure or the Omni, all good hotels and all under $90 or so per night by bidding method.
The best agency is Eleganza, very pretty young girls, almost all young 18-22, total GFE but some of them struggle a bit with English. Then again I presume that you are not looking for a reading of Shakespeare's Othello, if you want that you can hire Stu Gotz.
Montreal is the best hobby destination in North America bar none in terms of price, quality and legality as outcall escorting is legal.
Other good agencies are Chloes Playground, Montreal XXXtase, and Asservissante. Stay with the well reviewed core agencies and avoid the bait and switch agencies some of which advertise on MERB.ca which is your best source of info on the Montreal scene.
There is a good incall place called 2214 which is located on 2214 Rene Levesque (near the Sheraton) but you need a member referral.
I been going to Montreal regularly for 10 years, it is still a paradise for escorts and strippers but not like 10 years ago when the exchange rate was 1.6 to 1 US dollar.