The site is legit in that they do sell an actual ticket, but there are many catches. First, they won't give you a seat assignment so expect to pay for your seat or wait until the day of the flight and get stuck in the back.
Second, any information you give to their customer support may not be transferred to the airline. To be specific, British Airways did not have my passport number and required that it either come from the travel agent or that I appear in person at the airport 4.5 hours in advance of the flight. Needless to say Cheap Fare folks were not helpful and I essentially lost the last day of my trip and was super stressed that I was going to arrive at the airport and find out that I did not have a seat. Don't count on any kind of customer service or help.
Their online chat function is not manned so you had better have access to a phone if traveling internationally.
I wish I had just shelled out more money rather than wasting so much time and enduring so much stress. Lastly, their website showed that I was booking seats on Iberian airlines and the actual flights were American (Awful) and British Airways.
Reason of review: Order processing issue.