Here's a link to show what they might look like.
Personally I think my Chorkie (chihuahua/yorkie), Duchess in my avatar is a Cutie. BUT some people don't like any mixes.
It's all what you like. I have seen the chiwennies and they are cute.
http://www.dogbreedinfo.com/dorkie.htm
It also depends on which parent is which breed. I have seen some chorkies that look more like chihuahua because dad was a chihuahua. I was told they tend to look more like dad.