I like how they are very efficient in their work as well as being flexible to changes during projects.
They're also pretty good about keeping you updated throughout your project! Nothing really - just get it done quick but don't rush them if there's anything wrong with what THEY'VE created for YOU (and not necessarily YOUR product). We hired them because we needed help getting our website ready for launch. It was an ongoing process over several months which included creating new pages/sections, adding functionality etc.