It would be really nice if the App and the website gave the same results.

Last night I was booking ORD-SJO-PTY-ORD.

The app found better flights - a route for PTY-SJO-ORD getting home 4-5 hours earlier while the website wouldn't pull it up anything other than PTY-IAH/EWR/DEN-ORD. But the App wouldn't let me choose seats. Finally booked through the App anyway, and then went to the website where I was able to choose seats. Stupid.