I went with Flightsbank for trip, and I CANNOT recommend it. Here's my angry review from Trustpilot - pm me for more details...
WARNING: This company took our money and issued a reservation 6 months before travel, but never issued a ticket. Never contacted us about changes that airline made to reservation despite Air Canada sending 5 mail updates to Flightsbank LLC. Upon trying to check in 16 hours before, there was no ticket and multiple changes to reservation, with both outgoing (2h change) and return (24h delay) flights changed. Have been in contact with customer service agents Sean and Mark. Sean completely ignored issues we raised and instead moved to issue ticket (but no ticket was ever issued). Mark found flights we specified (with flight details for all flights) but was unable to do more for 6 hours while waiting for their ticketing office. Mark finally disappeared out of contact without issuing ticket; instead disconnecting phone, and not answering emails. Really, disconnecting phone! So much for "24/7 customer service". It is now 13 hours since we first contacted Flightsbank, and we still do not have a flight, nor will we likely make it today. Do not go for this company no matter how much cheaper it is compared to buying directly from airline