Here's my $0.02:
I looked at the Genesis with my dad several months ago. We looked at the V8 version with the tech package. I felt that the interior had fantastic materials with excellent build quality. Unfortunately, the interior lacked the sophisticated feel that I would expect from a car in this price range. My dad drove the 4.6 version and was quite impressed by it, but I didn't drive it. I rode along in the back seat and felt that the ride was decent, but the suspension was a bit lacking in refinement, especially on rough roads.
Aside from those two shortcomings, I think the Genesis is a great value. The V6 is probably a more logical choice since it doesn't give up much performance compared to the V8, plus it isn't as nose heavy (better weight distribution). I plan to go back to the dealer eventually and test drive the V6 version.
Also, I think it's very likely that the Genesis will have excellent reliability. Hyundai is trying to demonstrate to the market that it can build a solid vehicle for the luxury segment, so reliability is likely to be one of their top priorities. They are probably trying to follow the same path that Lexus took with the LS400 in the early 90s-- build a bulletproof vehicle that offers fantastic value compared to other vehicles in its segment.