I was in Beijing last October for 3 weeks. I took metered cabs at least 2 dozen times, sometimes late in the evening. I didn't encouter any problem.

There were a couple of times the drivers had no idea of the places I wanted to go; but I didn't completely blame them. I previously visited Beijing in 1995, 1996 1998 and 2001. Each time, I was surprised to see how much the city had changed. The transformation is truly amazing.

I visited Bangkok and Beijing on the same trip 10 years ago. Then, I would say Bangkok was a more modern city; now I don't think it is even close (To be fair, I think Bangkok may have a better airport).