Love the rational behind LastMinute 's search algorithm, and it's incredibly usable.
Unfortunately, it linked me to questionable travel agencies: SmartFares and BravoFly. Just before booking with them I searched online and found droves of complaints. SmartFares underreports the prices, then tell the customer they must pay more, and do not typically allow cancellation, even though they advertise that free cancelations. Bravofly, as well as SmartFares, both listed flights that were unlisted on the airlines main website. When I called either agency, after a search process, they told me the flight was no longer available--despite the fact that it was still listed on the website.
It's important and effective for LastMinute to search many different sources for price listings, but the developers really must take more care to vet the agencies that they are linking to. I feel that I narrowly avoided losing several hundred dollars on a booking with a questionable agency.