What are some alternatives?
When comparing Kraken and Coinbase, you can also consider the following products
Bitfinex - Bitfinex is the largest and most advanced crypto-currencies trading platform.
Binance - Cryptocurrencies exchange platform
LocalBitcoins.com - LocalBitcoins.com is a person-to-person bitcoin trading site.
Uphold - Move, convert, transact and hold any form of money or commodity. Instantly, securely and for free.
Electrum - Electrum is an easy to use Bitcoin client.
CloudFlare - CloudFlare can be used by anyone with a website and their own domain, regardless of your choice in platform