Note that Class D with efficiency in the 90's is becoming (rapidly) the industry favourite. On a 0.35um high voltage IC platform, the size of 1000W 6 channel amplifiers is astounding.
The selection between various class of Amplifiers is highly dependant on the modulation scheme requirement, as an example QPSK modulation modulation does not require highly linear Amplifier hence could be implemented in a higher efficiency topology. Hope this helps