I just bought the game! It is really fantastic, it is MUCH better then HoMM IV. It reminds me of HoMM III. actually, with some differences. The strategic AI is awesome. I am on mission 5 in the first campaign, and the AI is coming with huge armies, I failed on the mission 2 times so far. It is not scripted, for sure, since I defeated a hero who had normal devils and like 300 other creatures...the AI fled from the battle, and a couple of weeks later the same hero arriwed to my capital...I was like OMFG...that time the hero had like 15 upgraded devils, and like 700 other troops...I was wasted.
It is nice to see that the AI is so neat, even better then it was in HoMM III.
However it is weired, because theres only a couple of maps in the game to play skirmish or MP. I dont understand why is there no random map generator...but overall the game is superb, I had 2 multiplayer games so far, 1 lasted for like 4 hours.
If you liked HoMM III., this is a must have.