Is there genuinely a compelling reason to use different brands of hardware wallets in multisig setups? I am contemplating using a series of Coldcard hardware wallets in a multisig setup but some people suggest that it is more secure using different brands within the same multisig setup. I have also contemplated combining Coldcard hardware wallets with Blockstream Jades.
The compelling reason to use different brands in a multisig setup is supply chain risk. Let's say you had a 3-of-5 multisig/threshold setup using brands A, B, C, D and E. A preinstalled vulnerability in the device or firmware of A would not cause you to lose your funds as brand A wouldn't have enough keys to move your Bitcoin. There would need to be preinstalled vulnerabilities in multiple products across different companies (and possibly jurisdictions) which would be much harder to pull off. If A, B, C, D and E are all the same product from the same brand a single supply chain attack could cause you to lose all your Bitcoin. Michael Flaxman discussed supply chain risk on the Stephan Livera podcast in August 2019.
Security is always a complex, multifaceted topic. If there were a dearth of competent, trustworthy manufacturers of hardware wallets/signers then you might still choose to take the risk on a single manufacturer for all five devices A, B, C, D and E. In this case the diversification benefit may be dwarfed by introducing multiple inferior, less trusted devices to your setup. Also the implementation of a multisig setup using multiple different devices is slightly more complex and increases somewhat the prospect for errors in the multisig code or in the user actions (backups etc).
We can't do product evaluations on this site for good reason but the two manufacturers you mention would be among the most trusted and competent in the industry. You may also be interested in the products that Michael Flaxman recommends using in the 10x security guide.