I used it for a complicated round the world itinerary.

My first competition didn't get any takers ending with no flights, but I contacted support and they re-ran it and I got about 8 different itineraries - all cheaper than expected.

Funnily, there was $1000 to be saved by flying from Melbourne to St Lucia (Carribean) via London (~15,000 miles) rather than via LA (~11,000 miles). That made no sense to me at all!