the term 'best' really comes down to what you deem to be the most important factor. me, personally, at least when it comes to BTC and ETH, I value security over convenience, and so I always recommend going with a hardware wallet like Ledger. there are definitely more steps involved when it comes to sending from a hardware wallet but at least you have the peace of mind knowing that it's basically unhackable, and you're 100% in control of your wallet. If you leave it on an exchange then you always face the possibility of a hack but, of course, with the bigger exchanges like Coinbase, Bittrex and Binance you probably don't have to worry much. However, there's also the consideration that many projects (e.g. ICOs, airdrop campaigns, etc) require you to send certain coins/tokens from a wallet and not an exchange (wallet) so that's another reason why keeping it in some sort of a wallet, whether it'd be web-based or hardware, is still preferable over keeping it on an exchange wallet.