There was mention in a different thread about someone on TMob that was getting 80Mbps + throughput on their LTE connection, which I guess is a result of CA.
You could just use SpeedTest.net app to check your speed.
Alternatively you could dial the engineering number on your phone to get to cellular diagnostics.
dial *3001#123456#* then press call.
Although I'm not sure what all the metric mean.