I just received the December issue of PSM which has a review on MK: Decepion in it. For what it's worth, they gave it an 8.0.
For the most part they give it a good review including the online play. The only gripe is the 'Killer Instinct' style combo breaker. They comment about how easy it is to pull off. I tend to agree with this. It should have been a harder maneuver than just F+Block to break a chain.
Anywho, they liked it, just not quite as well as Soul Calibur 2 and VF Evo, they both recieved 9's.