exchange is nice because if you hold a lot of coins they handle all the updates and account security. Poloniex took care of the ETC thing with the replay bugs so holders didn't get scammed out of stuff. I got maybe 20+ altcoins I hold on there... the only issue is if they de-list a coin, then it's an issue. But they warn in advance of doing that.
This looks like something you are more inclined to like, but the number of coins is limited: https://coinomi.com/
I think a lot of this fear of exchanges is perhaps over-exaggerated. Think of it this way, if you get hit with a bug affecting that coin and lose your stuff because you had it in cold-storage and no one to micro-monitor your altcoins for you, you lose the coins. Where as an exchange handles the technical stuff on the back-end so you don't have to worry about it for many coins. Only issue I suppose is if the exchange is compromised... could happen but not sure it's a huge fear for me since the US government is breathing down their neck with regulations.