It's okay, but it's no Hipmunk.
Kayak doesn't even come close to this. At best, you can set the month of travel; useless for most busy people.
I still think the hipmunk interface is more humane.
I find that Google's innovation for almost every one of their products is in saying "we have oodles of data, how can we display it effectively"? They have done well at collecting and quickly accessing large amounts of data, linking loosely coupled sets, and in some cases, adding meaning (image searches understand the concept of "bright" or "dim", for example).
But I rarely see them taking the data they have and merging it in a way to create new meaning or value. Hipmunk, beyond co-opting a gantt chart, did this with their "agony" score. Google not only didn't try here, they didn't try for local search either, and just acquired Zagat for their score (and brand name and loyal following, etc.). And many startups offer meaning above and beyond that combined in the data: through their experience, their ability to merge context from being subject matter experts, or just their flexibility to experiment without a spotlight on them. Google tends to stop short of any of these.
So, yes, it's no Hipmunk: it's a typically well done Google product taking hairy data, merging it up, and displaying it well. Doing more than that, however, is left to the rest of the world.
(Though, one wonders why ITA didn't do some of these things before when they first created this better way of looking at flights a few years ago...)
Now, if the metric is useless or synonymous with some of it's underlying drivers, then you are right, nothing there. I find the agony score to be more useful than any small combo of filters, but perhaps that's just me.
BTW, ITA released their "matrix" front end to the world (http://matrix.itasoftware.com/) around a year or so after Orbitz and others licensed it. The clicks still took you to externals to complete the purchases, but new filters and capabilities were often tested on the live ITA site before 3rd parties took advantage of them. The problem I always felt was that they were just new filters: fast, live-response, rapid return filters on very large and nasty data, to be fair, but still just filters. I enjoyed sites that added additional context to the flight experience, few though they have been.
Again, thanks to both Google for organizing hairy data, and startups for doing more with the data. Glad both have room to play.
That being said, it is rare that I can find a better rate than what I see on Hipmunk, and their agony ui is still frickin' amazing.
Google, on the other hand, gave me exactly what I needed at prices competitive to Orbitz. It was a bit disappointing that when I was done, I had to buy the tickets through the carrier's site, but it still found me a flight at a good time for a good price.
Oh, and getting tired of Himpunk's promoted ads on the site that shall not be named.
Thanks. I didn't know about Hipmunk. I have been using mostly Kayak and, more recently, Google.