One of my favorite techniques to learn was how to crochet in a spiral...you end up with a project that is beautifully and evenly striped.
One of the biggest hiccups when you use two colors and crochet in the round is of course the 'stair steps' that happen when you don't join your rounds. It might look great from one side, but I personally don't like the way the other side ends up looking.
The trickiest parts about spiraling are keeping track of your rounds and making sure your different yarn colors don't tangle around each other. I'm rather good at keeping track of my rounds (unless distracted by the kiddos...), but honestly I'm usually too lazy to think of something to keep my yarn from twisting together.