What are some alternatives?
When comparing Poloniex and ShapeShift, you can also consider the following products
Coinbase - Bitcoin, safe and easy.
changelly - Exchange alternative cryptocurrencies.
Binance - Cryptocurrencies exchange platform
Shiftex - Cryptocurrency Exchange at the best rate. 100+ Altcoins
CoinSwitch - First cryptocurrency and altcoin exchange aggregator.
LocalBitcoins.com - LocalBitcoins.com is a person-to-person bitcoin trading site.