After playing the epic Dead Space 1 and the decent enough Dead Space 2, I was looking forward to this one. After 1 hour of play I switched it off really disappointed. It goes for action rather than the creepy, downright terrifying, leap out of your skin moments of it's predecessors. A few days went by and I had an afternoon to spare so I went back to it. 4 hours later I found myself strangely drawn in. My expectations had lowered and I'm actually enjoying it. I set it to one of the harder levels and I had some very satisfying battles where I genuinely had to pause after to catch my breath. Unfortunately there were some frustrating moments where I couldn't progress no matter how devious I was (and I tried everything). I'm afraid I also lowered the difficulty level to get things moving again. In summary : Is it the worst of the three..YES. Would I have preferred the formula of the first 1...YES. Am I having fun all the same...YES. Suppose that's what matters really.
Edit - Just finished it and the later stages were great. Things picked from about 50% of the way through onward. Overall I thoroughly enjoyed it.