I already booked mine with iscourier.ca Immigration Services Courier. My cousin used them last year. His application was received at 8:17am. (Stamped receipt)
I wasnt able to get my application in the cap in 2015 when I used UPS. this year I used iscourier.ca and made it in the cap :D
A friend of mine told me about them they are a bit pricier but they have a money back guarantee so it was worth it