Hi suprasport and everyone else. I am a new Lexus IS220d owner and thought I'd give my input for what it's worth!
Bought my car in October 2012, a 2006 (06) reg with 59k on it and FSH and paid £7495 with independent 5 year warranty. Previous car was a 54 plate Audi A6 2.0 TDi and fancied a change. After reading post's on this forum and driving for a few weeks thought I'd made a big mistake.
Main concerns were MPG - initially around 43, now around 47 (approx 570 miles on a full tank)/ (Audi was returning around 49-50) and reading about all the problems in this forum. Got to the stage where I thought on trading in for 57 Mondeo for same price as purchased. I was shocked to learn I would only receive £5500 tops after 4 weeks of driving, £2000 loss was not what I expected from a Lexus, supposed to be slow depreciation!
I am now warming to the car, very comfortable/ smooth and quiet to drive (little road noise even compared to the Audi). MPG has improved - added some BG244 and AR6200 fuel additive. Gear change takes some getting used to, have had to change my driving style as others have mentioned. I do use 6th gear over 60 though sometimes the engine feels as though it's struggling a little and just ticking over! May see about getting EGR cleaned as mentioned in other posts.
Lovely looking car - silvery blue. Anyone I have given a lift to remarks on the looks and how comfortable it is, if only the MPG was better. As someone else mentioned forget about paying a few extra £££'s per month on fuel and enjoy the drive.
I cover around 260 miles per week with around 10% town/ 20% motorway and 70% A country roads. Good luck with your choice, if you get a well looked after one hopefully you'll reap the benefits.