I never drove any Lexus.
I never sat in the IS, either. But I sat in many Lexuses, mostly GS including the all-new. What always shocked me are the buttons: squared, grey, shiny. Awfully old-looking...
I would say that these cars are lifeless, too perfect to be interesting. Maybe it is the Japanese idea of a car, a perfect machinery...But it is not my idea of a car.
I read in many reviews that the IS was not very comfortable, without feeling very sporty...
Anyway, I prefer the Germans because they have charisma, they have character. Not as much as the Italians, but...the Italians sometimes have a bad character and that is not always good...
Lexuses are a bit blank to my eyes. But I reckon they are very valuable, very good cars. For someone that wants a luxurious, reliable, discreet car they sure are worth a look.
My choice here is the C-Class, I love it. It feels very solid, build to last, it is very pleasant to live with, comfortable, very good-looking. I find the old Benzes values in this car and I like it.