Jeff-
Mostly everyone in my area does MIX! It's who can do it better, and more creatively with perfect timing. Same thing that makes a famous DJ with a following better than the next. How entertaining is the performance?
Lyrical play, matching key, looping/sampling, scratching, the way the song comes in and out of the song in an exciting way, reading a crowd, and highly underrated, song choice is what separates one DJ from another. For example, If I was up against Taso, I would probably have them come check me out, listen to a mix or video, or come by my studio to watch a live set. It's up to them who they felt best could rock the party!
I know plenty of guys around here you can mix well, but it doesn't "tell a story," lacks energy, and is boring, kind of like what Pyro does.
Generally, everyone I compete against has.a mixtape. The client decides whos they like best. In fact, I even tell them to ask for a mix from a company you might be deciding on.
And with all due respect, I say, if they cannot provide you that, then they are simply pushing play, like Uncle Bob could do. I also say that you wouldn't hire a photographer without seeing pics, so why would you hire a DJ without hearing a sample.
Crap, I just pulled out more hair.