I use vinyl, cd, loop sampler (when possible), effects and files when playing, hell I even read from science books on top of tunes when playing downtempo stuff.
Bad players (and dj's) are bad no matter what format you are using, crappy cd players are the worst, but if you learn how to play with lousy equipment you can handle almost anything that comes in your way. If you limit yourselves on one format only you're missing quite a bit from art of dj'ing. Cd's has loop function that can be used creatively if you have imagination. It's mostly the person behind the equipment, not what format is used.
I recently moved on to vinyl by the side of cd's because half of the stuff I like to play has to be bought as files or vinyl other half I can find on cd's. I prefer _all_ the tracks I play are legally obtained, support the artists and labels. In a way you can't compare cd's to vinyl, I think they are great ways to support each other, rest is up to you.
I'm not limited to playing only certain type of stuff, I play from ambient to 200+bpm "sonic warfare", jazz, blues, rock, beat poetry and anything in between. If it fits the mood of the mix it fits there.
My crappy cents...