Uniswap because have more trading volum like Idex,on uniswap daily volum is around 750 milions $ and idex have around 200k$
I myself haven't tried idex so I can't give any comments, but if our friends say that uniswap trading volume is superior, it could be that Uniswap is more superior because volume cannot be separated from one's interest and the trust that one has.
Frankly, I am a Uniswap user, it seems simple and easy to use and not too dizzy because almost all coins can be done there, remember, like etherdelta, it is a place to hold all altcoins that are just about to be registered or are currently running.
but maybe my problem is when using uniswap
and compared to the exchange of coins, it is clear that the fee is quite expensive and this seems to be a problem for me, but if it is urgent, yes .... most people will sell on uniswap