what do you use wallet or exchange for? Do you want to trade or hold ?
If you hold on a mid term or trade, you should use exchange. And hold your coin for security, you should use hardware wallet.
I think the wallet is the best place for safe coins. Coax it have a reliable and easy to use.
It depend on you're a trader or long term investor.
If you are a long term investor then the best you should store your coins in hardware wallet, it's safer. But if you are a trader you need to store all your coins in exchange sites, it will convenient for trading and saving fee deposit and withdraw.
For me, i'm using both because i use 60% my capital for trading and 40% for long term investment.