Back in 2017 i was seriously considering buying a 2015 Audi Q7 TDI (turbo-diesel) Prestige. At the time, my daily drive was a fully tuned 2012 Audi S4. You can see i like Audis and i am pretty capable to maintain and work on them if and when needed. My Audi S4 had over 100k miles when i sold it, it was far from stock, it was driven pretty hard and it was very reliable, as long as i maintained it properly (correct fluids, parts, etc at the right intervals). Again - i work on my cars and i don't pay the dealer for every little thing. Taking an Audi or any German car to the dealer for repairs/maintenance will be a very costly experience. I call it a rip-off.
Since we have 3 kids, the S4 was not cutting it, so i was looking at larger SUV options with 3rd row seat. The Q7 was on top of my list, especially with the very capable, high torque and good MPG TDI engine. The one thing that bothered me at the time was the very dated infotainment system in the 2015 Q7. Even though this was a 2015 model SUV, the body/interior was introduced back on 2008, so i was looking at 2008 design and it was so so obvious. On top of that, the price for a low miles Prestige trim was close to $40-42k.... and dealers were not interested in negotiating.
This is where my 2017 Mazda CX-9 Signature came in the picture. By pure luck, i found it at a local dealership - Fully Certified, with only 8k miles, for $36k. I test drove it 4 times and i really liked it. It was practically a new car, with great warranty, great looks, much more modern interior than the 2015 Q7, nicer infotainment system and decent gas mileage from the 4-cyl turbo. Yes, less torque than the German TDI, no quattro awd, but for a daily driver, i figured the Mazda will be sufficient. So i pulled the trigger. Still happy with it 3 yrs later, and i am not ready to get rid of it yet.
I did discover some weaknesses with the CX-9, especially around the primitive AWD system, the so-so audio system, so-so seats, half-baked "luxury" options, and overall lack of real power from the 4-cyl turbo. I still love the looks, inside and out. I also like the handling....and the fact that it has been trouble free and i got it at a great price. It gets the job done well.
Earlier this year, my wife decided that it was time to upgrade her daily driver and we sold our old but super reliable Lexus GX470 (great SUV). After some searching and serious negotiating, we pulled the trigger on a brand new 2019 Audi Q7 Prestige 3.0T. We bought the car for $13K under the sticker price because the new 2020 model was starting to show up on the dealer lots. It was a great deal, almost too good to pass it up.
Well.... let me just say this - it is VERY obvious why the Q7 costs more than the CX-9. The Q7 is in Prestige trim (top level) and my Mazda is Signature trim. Comparing the two SUVs is almost unfair. One is a true luxury SUV and the other is a true "Premium" SUV. The Q7 is more powerful, much more quieter inside, handles really well, better AWD, better seats, better leather, better lighting, better brakes, amazing dashboard (digital cockpit is very cool), nicer sounding stereo system, glass roof, roomier second row seating, better done safety features, really well working cooled and heated seats, same if not better MPG, super smooth 8-speed ZF transmission.... and the list goes on and on. So yes, Q7 is a more expensive vehicle, but in my opinion, there is a list of good reasons why it's more expensive.
If my budget is $36-40k ... i still feel the CX-9 Signature is a strong choice if new. However, i would also very seriously consider a
certified used ('17-18) Audi Q7 3.0T in the same price range. It's just a better built, true luxury SUV.