On the positive side, the information provided on the final map is both interesting and useful, and I like the format that it uses.

On the negative side, the time to resolve my entry of the airport code was very, very long, as mentioned above. (It did seem to get a little faster as I performed additional searches, but the first lookup was interminable.) Also, the top left side of the page is too busy, with both the "The Great Circle Mapper Air Distance & Flight Time Calculation" and "Enter Airports" in the funny white script with an arrow overlapping.

If the speed of the airport code lookup was better, I would use this site.