What is the difference between Bittrex and Coinbase?

Could you elaborate on the key differences between Bittrex and Coinbase? Both are leading platforms in the cryptocurrency space, but I'm curious to understand their unique features and how they differ from each other. For instance, is one more focused on altcoins while the other prioritizes major cryptocurrencies? Do they have differing security measures? What about their user interfaces and ease of use? I'd appreciate a concise comparison that highlights the key differences between these two popular crypto exchanges.