HBTC is a cryptocurrency exchange that was previously known as BHEX, or Blue Helix. The HBTC exchange offers traders a variety of currency pairs, as well as other trading options such as options contracts and and OTC desk. As part of the company's re-branding, a token swap will be held to allow holders to transfer their BHT tokens to HBC.

Kraken is a US-based cryptocurrency exchange and one of the largest bitcoin exchanges in terms of volume and liquidity.
It provides Bitcoin pricing to the Bloomberg Terminal and has considerable influence on the overall crypto market. Kraken offers a number fiat funding and transfer options.
There are 18 BTC pairs and 16 USD pair to trade
Fees vary depending on the volume - for main trading pairs this is between 0.1-0.35% - however for other less common crypto pairs the range can be as low as 0.05% or as high as 0.75%. There are also 0% fees for some trades.
Withdrawals and deposits are variable depending on the method - although in general all fees are 0.19% with a $20 minimum.