Had my Ghibli done at an independent after the dealer quote made me wince, and it came out at roughly half. They showed me the old pads and the rotor readings without being asked. Ask to see the worn parts when you collect it, whoever you pick.

Did a mobile inspection on a Tahoe last year in Dubai Marina and it was decent. The guy had a scan tool, paint meter, and a lift, and he found a leaking rear main seal I would've missed. Frame rust on these trucks is the real thing to push on though, so make sure it's in the report with photos.

Warranty holding up comes down to whether the sale is registered through the official system at point of purchase. Ask the technician to register it in front of you before they leave, that single step is what actually makes the warranty enforceable rather than just a piece of paper in the glovebox.