Yes! The sound with the USB stick is noticeably brighter and has more presence than when played via my Bluetooth connection. I don't have any way to quantify this, but the difference is noticeable for me (and I wasn't expecting it).
Also, my Android phone has fairly regular connection drops with the car at certain large road intersections (not sure why this is the case), causing the phone-car connection to have to be restarted before Android Auto can continue (and obviously any music that might have been playing from the phone is interrupted in this process). Also, when using Bluetooth to play music, I sometimes get short momentary drops from time to time for unknown reasons (not a huge problem, but a minor annoyance).
This is the memory stick that I've been using":
SAMSUNG Type-C™ USB Flash Drive, 64GB
Tho fairly expensive, it's high quality, fast, small, has a metal case, and is pretty robust (at least according to Samsung:
"waterproof, shock-proof, magnet-proof, temperature-proof, and X-ray-proof"). Not to mention, this specific stick was recommended by Toyota support.