I'm not a fan of Google Trips ... yet. I think it has potential. But so far it's too limiting. It constructs its own ideas of where I'm going, which may or may not be accurate. And it has limited manual override capability when it messes up, which is often.

Overall, I prefer TripIt by a lot. But keep an eye on Google Trips -- this is an early iteration and I wouldn't be surprised if it improved quite a bit in the near future.