It's tough for us newbies out there.
I started using Bittrex but it's really a little too advanced for me. Also, for some reason for some currencies, there's a huge outgoing fee if you wanna leave the platform. I had some PTOY (at the time of writing this, it's ~$0.5), and it asks 2.5 PTOY to just transfer it to an etherium based wallet.
Then I used BlockTrades to get some Steem, which is the original method Steem directs us for exchange. But I found much better rates elsewhere so I gave that up too.
It came to the point where I'm checking price for each exchange on each platform. For example, for buying Steem today, I found Changelly both the cheapest, and also the easiest to use. However last weekend, buying BAT was much cheaper on Bittrex.
So far, out of these three, I am probably going to use Changelly the most often. It's also the easiest for a starter. Maybe for larger amounts I might do these double-checks again though.
Which exchanges do you use to change between cryptocurrencies? Let me know in the comments, let's share the knowledge!