If we are talking about Lexus I must say that the most comfortable car I've driven so far is 2008 Lexus IS-F. Later series are also cool, though I feel more comfortable in this particular series. My second favorite would be Jaguar XE. It's both comfortable and economic. I have and if I manage to sell it in this year I'm going to buy the car.
I really plan to buy a lexus is300 in the near future. I have long dreamed of this car. My friend gave me his lexus is300 to drive, I have the most pleasant impressions. I know he invested a lot in modifying this car, but I am sure that as my project the lexus is300 will be good too.