Sorry guys/gals. Was late and I was tired when I posted.
It's a bit difficult to compare my 37s to a new Q50s. For one, my car has 44k on the clock. For arguments sake I'll stick with what I thought of the Q50s.
Driving Dynamics - The Q50s inspires a lot of confidence. The steering is very direct with zero wheel play. The Q is sure of itself and planted with little to no roll/lean. This is likely due to the new direct adaptive steering. When I agrresively drive my G the car tends to hop just a bit over road(bends and straights) imperfections. Not so with the Q. I didn't play with the steering drive modes. There's no way to truly get a feel for the system while on a test drive (not my test drive anyway) With the wheel in my hands the car does feel larger but only slightly. Note, overall the Q is larger than the G. I did play with the vehicle drive modes but only Sport and Eco. While in Eco mode the car is noticibly a bit of a dog off the line but that's what Eco mode is. Seems to cuts back throttle input just a tad to save fuel. Now Sport mode is where the car truly shines. From a stop the car sprints with authority (not that different from the G) Paddle function is the same as we've come to know. I do wish shifting was a bit faster but I guess that means getting a sports car right

I just feel there's more there but Infiniti is just not giving it to us. Not a bad thing just personal taste. I think they had a Hybrid in stock but I'm personally not interested..
Interior - While very upscale in fit, finish and material.. this may just be taking the vibe from the M series. Which is okay by me. Just don't expect anything fantastic unless you've never sat in the M series. Nav and app screen were not available for testing. All are due for a software upgrade which they will not apply until the car has a buyer. I've read some folks complain about the app screen being slow. No way test myself if true or not.
I made sure I was in a comfortable driving position and then sat in the rear seat behind the driver seat. Lot's more leg room

I'm 5'9! The pillar has been moved way forward. In my G, all things being equal, I can't get out without kicking the door panel. I need to twist and squeeze in order not too. Huge bonus for me.. Not that I let anyone else drive my G but my daughter sits in the rear

Seating is comfortable but Infiniti has done away with the thigh bolster adjustment. Leaving only the torso adjustment

You're still able to extend the seat under your thigh. In the G Sport seat you're able to adjust thigh and torso. Screen, dials and buttons are all set within my reach. Rear seating is good and now sits a bit further rearward at an angle.
Exterior - The Q50s front fascia is aggressive and makes a bold statement. You either love it or hate it. The unique lighting treatment sets it apart. AWESOME! I'm not as high with the rear tails. Would have preferred they kept something inline with the G. Round LEDs but it's not a deal breaker.