Wow, I'm surprised your wife likes the way it drives because I think it belongs on the track, not the street. Before we bought an Audi Q5 for the wife, we test drove several models from Infiniti including the G37 and thought it was way too loud and shifted very rough. In fact, I almost threw up after getting out of the car after a 10-minute test drive because of the motion sickness I got. I realize I get motion sick more easily than others, but it was the only car brand that did it to me (and we went to Toyota, Lexus, Audi, VW, Volvo, BMW, and Acura).
Did you feel it was very spirited drive compared to the other brands you test drove?
EDIT regarding Audi reliability: The poor reliability for Audi over the past 5 years were all due to the terrible 3.2L engine they used in all their models (i.e. as an upgraded engine in a Q5, or a base model in the A6). Since they came out with the 2.0T and now the 3.0T, reliability has improved a lot. In fact, Audi is actually ranked higher than Infiniti in the latest JD Power Dependability study. Also, here are the latest results from Consumer Reports, so we have 2 sources which back up my claims (Note the jump from last year of 16 spots):
Rank (last year), Brand, Best model, Worst model
1. (same) Scion, xB, xD*
2. (+4) Toyota, Sienna (AWD), Prius C*
3. (-1) Lexus, GX, CT 200h
4. (same) Mazda, Mazda3 (Skyactiv)*, CX-5*
5. (+3) Subaru, Legacy (6-cyl.), Impreza Sedan*
6. (-1) Honda, Odyssey, Fit
7. (+4) Acura, MDX, TSX
8. (+16) Audi, S4*, A7*
9. (-2) Infiniti, G Convertible*, G Sedan
10. (+2) Kia, Sorento (V-6), Sportage
11. (+14) Cadillac, SRX, CTS coupe*
12. (+10) GMC, Sierra 2500 (turbodiesel), Terrain (V-6)
13. (-4) Nissan, Armada, Leaf
14. (+4) Mercedes-Benz, E-Class Convertible*, E-Class (V-6)
15. (+2) Chevrolet, Corvette, Volt
16. (+3) BMW, 7 Series*, 328i*
17. (-6) Hyundai, Sonata (turbo), Veloster*
18. (-2) Volkswagen, Jetta (4-cyl.)*, Jetta SportWagen (5-cyl.)*
19. (-6) Jeep, Wrangler (4-door), Patriot
20. (-10) Volvo, C70*, XC70
21. (+3) Buick, LaCrosse (V-6), Enclave
22. (+1) Mini, Cooper Countryman, Cooper Clubman*
23. (-8) Chrysler, 300 (V-8)* 300 (V-6) *
24. (-3) Dodge, Charger, Durango (V-6)
25. (new) Ram, 2500 (turbodiesel),1500 (V-8)
26. (-12) Lincoln, MKX, MKS
27. (-7) Ford, Explorer (V-6, 4WD), F-150 (V-6)
28. (same) Jaguar, XF*, XJ*