I drove a 06 IS220d Sport for a few days last year and was impressed with the comfort, useability and layout in the cabin. The Sport seems to have a more torquey engine map than standard and is a nice drive with respectable pick-up in the higher gears.
Don't expect to fit the Ireland second-row in the back as leg-room is quite restricted. The engine is a little noisier than I expected in a car of this class and pedigree but overall a nicely proportioned, well-designed car; very decent and just that little bit unusual, adding to the car-park appeal.
Its a weighty beast; I got low 30's mpg over the few days, but I wasn't going mad on the loud-pedal.