Required reading and viewing for this post: The video of the Magic Painter and Paddy Johnson's discussion of it. "Berg" is the controversial religious figure discussed in the post, who produced and stars in the video equating God with an artist.
Similarities:
Central figure of preening male vanity who is in almost every shot.
Sexual undertones.
Personal cosmology that explains everything.
Differences:
Berg actually understands cinema, using cuts, wipes, dissolves, etc to create hurtling forward motion.
Berg's kitsch entertains while working on meta-levels, as opposed to austerely parading cryptic symbols.
Berg employs computer graphics and video technology circa 1989 that are amusingly dated but still wildly dynamic; Barney is mostly about weird costumes and sculptures flashed slideshow-like before a stationary or slowly panning camera.
One is the highest art New York museums and galleries can sanction; the other is YouTube trash passed around by savvy and/or Barney-indifferent artists.