I have only started playing Heroes recently, having purchased HoMM4. I have never seen or played previous editions of the game.
I found the game fascinating and absolutely addictive. At first it was a lot to learn, all this business about towns, schools of magic, heroes, creature abilities, and so on. I almost gave up on the game the first day or two as being "too intense" for the casual player. However, as things started falling into place, I became addicted.
The game is everything I have been looking for in so many other games, with just the right balance of strategy, tactics, adventure and role-play. My only complaint is that the game is not as stable as I would like, and I find myself being dumped back to the WinXP desktop at least once in any extended playing session. Thank goodness for AUTOSAVE. I don't know if that is a general complaint or if I just have a bad PC. Except for this issue, I think the game is fantastic, and I have played nothing else for several weeks now.
MY FAVORITE STRATEGIES
My favourite heroes are Knights, Priests and Nobles. Knights improve the fighting capability of an army, Priests keep your units alive and Nobles contribute to the efficiency of your towns (creature growth, income, resources, etc.). Any hero that is going to participate in combat MUST have some combat skills as well, just to keep them alive at the very least, otherwise I tend to specialise.
I also like to have one or two pure combat heroes (barbarians), and if I can develop the hero high enough to include a few tactics skills, then he becomes an invaluable part of any army. Such a hero, buffed by a good priest, is almost unstoppable.
The only gameplay gripe I have is that the units/schools that have
summoning capabilities (order/nature) have an almost unbeatable
advantage. With a few dozen genies in your army casting Illusion you can beat just about any enemy army.