Hello Mark, I drive a 2006 Lexus is220d and for the past 6 years-ish in my ownership it has been superb.
The basics come to this my friend,
Do you want a decently efficient diesel, relatively cheap to run and looks good but is pretty much the same as everyone elses,
Or do you want a beautifully designed, quiet, motorway mile muncher which is a joy to be in?
The IS220D in my opinion is not really designed to be involved driving, to let the back slide just a little as you take a fast corner trying to beat your home commute time. It is designed to wade gently through miles of motorway as you sink into the luscious seats, 6th gear, tap cruise control and settle down for the journey. It is an excellent car for what it was designed to do and it does it well. Just as any other, it occasionally has some problems but no more than any other car. Think of it like an old man, its all about taking it easy, enjoying the ride, no hurry to get anywhere, if you want the opposite ze germans churn out more than enough of generic m sport, amg replica s line tin cans to choose from :).
Good luck