I had a trip today in Bangkok from Silom to Fortune Town - 167 via Grab Car, which I took because Uber said 286 at the exact same time (probably surge pricing). The app worked fine (had to first do an App store update), in some ways easier than Uber.

Also used Uber to/from Silom - BKK airport. Was 460 to Silom, 473 back to BKK, both middle of the day. I used Uber Flash both times, both times cars not taxis arrived. Less than 5 minutes wait each time.

For the truly nitpicky, I took the Uber from Door 2, I wonder if walking down to Door 5 would result in getting a car faster, the app seemed to show the car starting from that end, like they were also parking waiting but probably pushed along by police, etc. - ended up waiting for the driver to loop back around to Door 2.

Cheers!