I bought HOMM3 a while back having enjoyd it a ton as a kid but had trouble getting into it as it was so obvious the AI was cheating heavily.

Is the same true of Disciples 2? I never played it but I do remember watching a friend play it some and it looked interesting.

I don't recall any obvious cheating by the AI, although this is based off of the campaigns where the actual AI players aren't really that much of a threat. In the campaign you'll find yourself mostly going against neutrals and scripted events, so not much is actually left to any quirks or vagaries of the AI.

I believe the AI may get resource bonuses multipliers at higher difficulty levels. However, the AI only ever uses level 1 and 2 spells, so I wouldn't worry too much about that.

In the original Disciples, AI was cheating as hell! It's uncomparable to HoMM3, there AI only got resources bonus and maybe decrease in cost. In Disciples, on higher difficulties, it also got infinite mana, and passive XP gain on heroes and units, so it forced you to play "against AI" not how you normally would play. At the same time AI was dumb as hell, so no wonder they resorted to cheating, in HoMM3 AI was much smarter on it's own. Here you can almost basically tell what's it gonna do, so it's a bit of a puzzle game (the AI will do this, even if it makes no sense at all, so i have to counter it with that...). Funny thing, with the amount of cheating it had, it's theoretically possible for it to basically wipe you from the face of the earth with spells and all, but it graciously chooses not to, which makes it even more illogical. I thought this sucked, but the game mechanics were so cool that i kept playing and still had fun, with a pinch of annoyance :D I think on easy it doesn't cheat, but then it's.. .well... easy :D

I only played Disciples II a bit, unfortunately I think the cheating is still present, don't know the extent though. But judging from their design philosophy in the first one, and since the game's don't differ that much apart from graphics, you can guess that the cheating is there still.

In a word: no.

While the AI isn't per se a stupid dummy, it's predictable and easy to beat. Any challange comes from the AI having premade units and it cheating during combat. The difficulty setting doesn't affect the game much. The fun comes from playing the campaign and beating the neutral units, but the AI isn't any good.

Not my experience with the fourth mission of the Empire campaign in Sacred Lands, where once you hit the chokepoint, the AI will right away try to obliterate whatever leaders are there with every spell it's got. Including Sinestra Ignis for 100 HP of damage (kiss your back row supporters goodbye if you didn't cast fire ward...) It's possible that the AI priorities were tweaked for that map, though, I suppose. I have to agree that it's a bit of a weird game in that you're focused more on hitting the dungeons and whatever other thing you have to take out for the mission goal, while the AI is more of an annoyance and only a real threat if you allow it to claim too much land & resources.

I haven't played Disciples II through fully, but I do notice that the AI combat tactics seem to be changed/improved some (more likely to try to flee if overpowered, for one thing, while I think the AI in the first game always fights to the death, outside of using "fear" abilities on it and stalemate for too long combats). I'm less sure about its overall strategy on the overland map, though. Possibly less excessive/incompetent use of the thief (in the first game I remember it poisoning a troll over and over, losing thousands of gold worth of thieves in the process.)

What I meant is it could have rain down spells even if you're far away (provided you're scouted, depends on a mission) making it impossible to move or do anything.

On the other hand I actually remember it doing exactly that on 3rd or 4th (don't remember) mission for undead on hard difficulty, which is why I never finished it, because my troops couldn't last any trek. And then there come enemy heroes with fully upgraded troops.

This at least I know for certain: it cheats mana, and it gets passive xp gain on all difficulties (i just played a match on easy). I think difficulty setting affects only the extent of cheating, not it's presence.

Oh, and btw, there's also Disciples III isn't it? Nobody mentions.

Which upgrade path did you pick for your warriors... zombie or templar? IIRC I found templars to be the better choice for the Undead saga despite only going to level 3 and having lower raw stats, because their ward against the four elements acts as an immunity when it comes to overland spells, and while the zombie branch has true immunity to death damage, the Undead themselves are the primary users of death magic. The spells "shadow" and "nightfall" are also invaluable to hide your parties from enemy castings. Undead probably do have the toughest saga overall, but I didn't find it so unbeatable as some seem to.

As for the third game there's a fair bit of discussion over on this thread:
http://www.gog.com/forum/disciples_series/disciples_3_improvement

I do remember picking templar because of that exact reason... I remember having some troubles with shadow spell (if that's the one replenishing fog of war), probably having a hard time keeping up with mana. Yeah, undead are the toughest, I think the sagas are lined up by difficulty, but it's definately not unbeatable, it's just that it took too long to figure out how to do that scenario so I didn't :P I've beaten all others by that time so I was pretty burnt out anyway. ALso as I said, I played on cranked up difficulty setting.