I suppose it is comparing apples with oranges, the CT is great as a city/short trip car where emissions and fuel cost come into play, easy to park and easier on the eye and a bit different from most of the other hatch backs.
I have never been able to quite put my finger on what market the IS was aimed at, like all the Lexus range it has plenty of kerb appeal and the Lexus quality goes without saying. It still didn't tick many other boxes though with high vehicle tax, limited rear passenger space, thirsty petrol engine and at 204bhp a 6 cylinder motor with 4 cylinder performance. I think now it has been dropped and the IS300 hybrid is on board with similar performance and only 30% of the running costs the IS250 will be available at bargain prices for the astute buyer