Agreed, the 200L 2.8 is a very under rated lens imo due to the fact that it lives in the 135L's shadow, and there is the 70-200 2.8 available. It obviously depends on a persons useage, but for me, out of the two, the 200 was much more versatile. I've sold my 135.
You often hear people talk about 'the low light capability' but f2.8 still gives better AF, as well as f2, and if you're shooting events f2 gives naf all DoF on a 50mm never mind a 135, as does f2.8 for that matter.