I have to disagree. I traded in my 53 plate Shogun for a 2007 (57) IS220d for the same reason mpg's. Sp far I have only had a problem with rattling in the drivers door. I phoned Lexus who booked it in and put it right, all within a couple of days.
Economy isn't the best for its size but it has great performance, and if the turbo is timed right it pulls like a train. I average about 35mpg round town and around 44mpg on a run, that is driving it enthusiastically.
I looked at BMW's, and Audis, both I found bland, I considered a Mercedes but they were too pricey. For what you get with a 220d I think it offers the best bang for your bucks.
The only real niggle I have is with the long range gearing, it takes some getting used to and 6th gear is almost redundant unless going over 75mph. Other than that I think it is a great car.