Dark Sonic au Dark Spine Sonic. One, arent they one in the same? I like Dark Spine Sonic better but I'll maoni for both.
Dark (Spine) Sonic Has Raw, Unsurpassed energy. However, It cannot be controlled easily.
Super Sonic runs on the energy aliyopewa off from the Chaos Emeralds. It may not be as strong as the wild power of that that comes from Sonic's rage but He can easily control the Chaos energy so it's pretty much balanced.
And so is my opinion. They're both cool but I have no "one" favorite.