It is generally considered to be a good idea to store your cryptocurrency in a hardware wallet, as they provide a high level of security by keeping your private keys offline. This makes it much harder for your coins to be stolen by hackers or malware. Some popular hardware wallet options include Ledger and Trezor.
Please note, MetaMask now supports more hardware wallets than just Trezor and Ledger. However, we have tested and confirmed both Trezor and Ledger work end-to-end for domain storage. Any other hardware wallets used will be at the risk of the user.