Ledger is based on a proprietary, closed source secure chip (NSA anybody?), therefore it is inherently less secure than Trezor. It depends on your level of paranoia thou
No. Ledger is powered by HW. 1 firmware which is open-source AFAIK and also
https://github.com/LedgerHQ/.
Okay, it isn't a cold wallet by definition, but it basically is a paper wallet which you can spend from without exposing your private keys to anything internet connected, transactions are signed in-device.
Right except about the similarity to paper wallet. You will have to expose private key in a paper wallet for sending Bitcoin unless you sign in an offline computer and if there is an offline computer, there isn't need of paper wallet.
You are right about the price thou, no reason to protect your bitcoins with a wallet that's
worth more than what it holds Precisely. If you only want to hold a small amount, Ledger or paper wallet or even a secure online pc is enough. Most people buy Trezor if they have many Bitcoins to hold.