Indeed, I decided to try it out (having never used it before) and was very impressed.
Historically my flight booking priorities were pretty much 100% price related, but now they're a combination of price and duration.
Alas most sites only let you order by one or the other (literal example: 35 hour flight for $1850; change the sort to duration; 15 hour flight $3300, scroll through the list for _ages_ to try and find the best combination of the two).
Then select the best option outbound, only to find out the return flight is 36 hours... Or that the 16 hour option adds another $800 to the price.
The HipMunk UI was really nice for finding good duration flights in both directions, whilst also making it clear the price implications of which return leg I used (which to me is uncommon, because so many sites treat them as disparate steps, so a change in return flight means you get kicked back to step one.
Not strictly comparing the experience to Google Flights (as I haven't really used it), but to a lot of other flight search sites I've used (Kayak, SkyScanner, WebJet, Airline sites, IWantThatFlight, HelloWorld, among others).
The HipMunk UI actually facilitated that search really well. Very impressed :-) (And it seemed to have equally good prices for the flights I looked at compared to other sites.)
