I can't speak to what things are like if you need to cancel or if your flight is cancelled, since everything went OK with my flight.
It was cheap, $99 round-trip within the country.
I had to contact customer service to ask a question, but their phone number does not lead to a actual person, it's all robot. I did have luck though reaching them on Facebook, sent a direct message to the company and someone called within the hour.
The online checkin for WestJet wasn't working, so I did have to checkin in person. Don't know if this is a FlightHub problem or a WestJet one.
I didn't realize until after I bought the tickets that they did not include checked baggage (only a carry-on included), so I did have to pay a little extra at the gate. I was also unable to modify any seats. I did have someone in my group bail on the trip and I couldn't cancel their ticket, but given it was under $100, it's fine.
No hidden fees, other than the baggage issue. The $99/person included taxes and everything.
So 3 Stars. It's cheap, but there are some service issues. Next time I will probably buy direct from the airline to avoid the headache of dealing with a third party, but I couldn't pass up the deal this time because they were much cheaper in my case.