Well, there's a reason your called "Backward" galaxy (just kidding)
It depends what you're after - DCD/DCC tend to be better in the one-off sculpt and paint departments (their use of metallics is gorgeous on most figures), but Mattel do better on articulation and consistency.
Mattel could never have made Warth or Kryb, but at the same time Soranik Natu doesn't have the necessary articulation to stand up straight and Atrocitus is permanently limp-wristed.
I'm not going to rehash any of the Stel/Atrocitus/Mongul/Nekron debates here, there are good and bad points to both figures in each pairing, but they do highlight the differences that people look for.
And yes, there will usually be a swing towards Mattel figures in the Mattel forums
Jo