Both of these wallets are great in the right hands. I actually prefer the Trezor because of the open source design. Open source will have more annoyances as "hackers" exploit the code (since they can see it) early on, but once the code is tried and true I feel better about using a product where millions of eyes are keeping touch! There are valid arguments in the other direction. I have never lost a coin using either wallet.
Well, not all users will prefer Trezor as the best hardware wallet because Trezor wallet is hackable but they already fixed this issue so it is safe to use as of now but not 99% safe.
The best hardware wallet for me is Ledger Nano S never heard any issue about this wallet until now and I heard just now about their new Ledger Nano X which has new feature but I don't know how safe it is compared to Nano S.
As I said in another post, bluetooth like the USB connection is just the interface you use to access the secured chip.
It makes basically no difference what kind of connexion you use, be it usb, bluetooth, LTE, Serial, it really doesn't matter. The actual security is in obfuscating the private key.
Being used by bluetooth would made an INSECURE device more hackable.
If the device IS secure like Nano S seem to be, it will also be through bluetooth.
To me the X is a Nano S with more memory and a bluetooth chip.
I prefer to use USB compared to use a Bluetooth because I heard that you can receive a virus like "Airborne virus" even the device Bluetooth is off if your phone Bluetooth is on and the source of the virus is from other phones with Bluetooth off you can still receive a virus. I experienced this before with Nokia n70 and my nokia 6600. So I believe that Bluetooth is not a good interface for a crypto wallet.