I always use centralized exchange because a lot of my coins came from bounties are listed in CEx before I withdraw. But when I am buying altcoin, I supposedly buy in DEX like idex and forkdellta. I buy in Dex because the price it too much lower compared in centralized exchange. In addition, the fee is lower also. And I sell them in centralized exchange. I trust only idex and forkdellta in terms of DEX