My boyfriend and I do distance so I have taken my fair share of Megabus between Toronto-Montreal. This is advice from a veteran Megabuser then...
AVOID MEGABUS LIKE THE PLAGUE.
They have the single WORST customer service of any company I've ever dealt with.
We've taken upwards of a collective 40 round trips (it's often more affordable) and the experience has been negative more than positive. It's gotten to the point where I'd really rather pay more for other options than deal with their bullshit any longer.
Consistently late, with drivers who lack any sense of customer service or generally wherewith-all. Wifi doesn't work more often than it does.
Recently, my boyfriend had a ticket for a bus. The ticket clearly said the bus departure time was 8:30. So, he showed up early for the 8:30 bus. Unfortunately, Megabus had made a mistake with the ticket so that he was actually signed up with a reservation code at a different time (7:30). The driver did not let him on the 8:30 bus. What's more, they made him PAY 109$ for a ticket to the 9:30 bus, even though it WAS THEIR MISTAKE that the ticket was misprinted. This meant he MISSED a connecting bus in Toronto and had to pay for a new ticket there too.
This is ONE bad experience of MANY. I can't deal with their incompetence or lack of customer service any longer.
Make the decisions you have to make based on affordability etc - but be warned, it might not be so affordable in the end when they decide to screw you over.