One of the partners at my firm recently got a Genesis V6. It's a superb-looking car (except for the cheap-looking wheels), and it has a lot of "luxury sedan" presence, even if the styling is a little generic and derivative.
It's wonderful to ride in. Materials are absolutely top-notch (my boss has the optional leather-covered dash, for the record), and build quality doesn't give up an inch to Lexus or Mercedes, in my opinion. It feels like a rolling bank-vault in the same way a Merc does, and the engine is silky-smooth and quiet. Heck, the entire car is library-quiet.
My understanding is that it floats more than a Merc or even a Lexus if you're caning it, but really, what percentage of E-Class or GS drivers actually cane their cars? If you drive in the sedate way that most people who own these cars do, and you don't care about badge prestige, I can't think of a single area in which the Genesis lags behind.