I'm still sorting that out. I've recently set up an account at bts DEX and agree with @tt-dogg regarding the risk of various centralized exchanges. However, for active trading the volume just isn't there yet on many pairs and the spreads can be quite wide as well. Now, if you are laddering in/out as suggested by our dear friend @haejin then you should be able to place your limit orders at bts DEX and they should be filled.

I currently have exchange accounts at HitBTC (the Troll Box is entertaining) and more recently at Bittrex. I'm using Coinbase to get real USD into the crypto system (BTC/ETH/LTC only right now) but their fees are too high to buy using their front end. But, you can set up a linked account with GDAX (coinbase back end) and trade with very low fees (0% for maker).

I'm in the process of acquiring coins with the intention of offloading them into private wallet(s) for long term hodl. Hope this helps.