One of the main competitor cars I've looked at while shopping was the 2010 Infiniti G37 sedan. In terms of pricing, it is very much in line with the Genesis. I was offered ~$34K for one with premium + navi packages, and ~$36K for one with premium + navi + sport packages. The G really does handle very well and still rides better than the Genesis. It's steering also has a more natural feel and the 7-speed slushbox felt more decisive. But obviously, there were a few issues that ended up being deal breakers for me.
My biggest gripe was that the interior felt absolutely cramped compared to the Genesis and the Acura TL. Up front, I barely had any head room with the seat set as low as possible, especially when equipped with the moonroof. The front seats in the sport package car felt a bit too narrow for my derrier, but the seats in the standard car felt roomier. The front seat (dis-)comfort factor alone was enough to dissuade me from the G. The backseat was even more cramped. With the driver's seat set to my best setting, I barely fit behind it. My head was pressing into the headliner, the knees were scraping the seat back, and my feet had nowhere to go! It's really amazing how little room these FM-platform Infiniti products offer (EX, FX, and M included).
Anyway, a few coworkers and I were chauffeured to lunch in a 2010 G37 sedan because one of my colleagues got a loaner vehicle from the dealer (he has a 2004 G35 sedan). Aside from the overpowering scent of air freshener, I noticed that the interior just wasn't as nice as I remembered it to be. All the trim pieces fit pretty well, but things really didn't feel or look a whole lot better than what you might find in an Altima or a Maxima. Finer details such as how the aluminum dash trim meets the aluminum trim on the door panel, or the look of the plastic buttons left a bit to be desired. If you compare the Genesis and the Sonata or Azera, on the other hand, you will find a pretty substantial difference in the quality. The engine note was as coarse sounding as these big VQ V6's are notorious for (far from the muted V8 intake rumble of the Genesis!). The ride was a bit softer than in the Genesis, but not by much, and the car didn't quite have that substantial feel that the Genesis offers.
Yes, I'm a biased source here, but I certainly do believe that for most people, Genesis does offer more bang for the buck than the G37. It may not have the sporting credentials, but the Genesis is really intended to be a bargain Infiniti M or Mercedes E-class. While it may fall short of those vehicles, it certainly does well to define a class between the entry level luxury models and the mid sizers.