Specs are quantitative aspects of the option such as the price
Pros
Pro
Great options for advanced traders
For example, Kraken allows you to margin-trade(choosing leverage is super simple) and shortsell currencies. They have currently disabled stop-loss, so be careful.
In addition to Bitcoin, Ethereum and Litecoin, you can trade a whole variety of altcoins. You can get a well diversified portfolio from just Kraken alone, without a need to buy different coins on several platforms.