I've been using TripIt for years (mostly free, but upgraded to paid when it came bundled with our corporate Concur package). I find it to be mostly good for my needs -- lots of useful features. The one frustration is the inability to add or import multi-stop tours, but I usually just manually add them as cruises, which is a semi-decent workaround. Other than that, I like the flight monitoring ability and the way I can use it to keep all my trip data in one place. I also like that I can decide whether to keep a trip private (personal) or shared (business).

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.