Unity3d CCD vs Steam DLC

I have plans to sell my game on Steam and I plan on making my various scenes DLC’s. I was wondering if anyone has an opinion on which service I should use, Unity3d CCS or Steams.
I figured if I used Steams, then I would be tied to releasing on Steam.
If I use Unity CCD then how would that workout if I release on Steam.

As a followup, if anyone knows of or used another content storage provider, that would be great to hear about.