I used Travel Nation to organise the flights for a round the world trip for myself and my wife. I found them easy to deal with, very helpful - nothing seemed too much trouble, were prepared to work with you to find what was best and were able to provide exactly what we wanted at the cheapest price. It was a no brainer decision.
Having just returned I can add that all the flights went smoothly with no problems at all.
Overall the experience with Travel Nation was excellent and would definitely use them again.