I've tried all the heroes at least once and won a shard with everyone but the Fighter. However, I really like the Commander. Being able to raise all your units offense/defense/hitpoints is amazing and saves having to trek back for more and untrained units. I haven't noticed the experience/morale skill being very useful though, think I'll avoid that one from now on.

I haven't used any spells above second level for the mage, so maybe i will change my mind later on.

Whats your favorite hero? Which hero/hero strategy do you think is most effective?

I'm not a fan of commanders, I take them as last hero, mainly to increase the score. It could be good when you have good high level units, but until then it isn't worth it, imho. As a starter hero, maybe it's good, but I prefer the scout.

A scout can:
1. kill dangerous bowmen/slingers/spellcasters from the distance.
2. weaken barbarians (and other units) so that they can be finished off by your barbarians in the same turn, and you won't be attacked by a barbarian gone berserk.
3. diplomacy skill to get those 2nd ring free settlement with resources for very little gold.
4. faster exploration.
5. pathfinding and mobility bonus

This is just the beginning, then archers will be devastating with double shot, can reach good command and magic skill, can sabotage, and good bows are much cheaper than good weapons, and cost less maintenance after battles. Pathfinding 5 gives amazing bonuses that compete with commander skills.

commander was somewhat nerfed in gog version.
Troll lair got static guard strength, earlier you could have troll lair in first ring or even in demesne with 2-3 trolls as guards.
Commander could win them with barbs and webs and then hire T3, basically getting easy mode.

Harpy nest still gives him enormous advantage.

How is GOG version different from original?

Scouts are pretty good, and I usually take them as starting heroes. But my favourite is the mage, if you can get them leveled up to use tier 3 crowd control spells or even tier 4 stuff they are the best. And if you can get them to level 20 they just rule with the double cast. They can very easily kill monsters guards, where the scout and warrior has big problems with the spiders and manticores, mage just pops a mass slow or cloud of terror and laughs. Plus managing the spells and buffing up units is more fun for me than just shooting stuff with the scout or melee with the warrior.
I have not played much commander.

They seem good changes, considering that horse archers are still weak (centaurs are way better) and healers are still essential.

Yeah, I certainly do enjoy the Scout and the Mage. I'll try Mage again when the Campaign gives me better spells. I didn't realize there was any use to the Diplomacy skill, but I suppose having it to grab a Centaur settlement could be good? Or something like that? I haven't actually succeeded in negotiating an alliance yet. I usually win the shard before I kill the necessary monsters and the option to buy it for those territories is always grayed out for me.

Alliances with nonhuman races are dependent on both the diplomacy skill and your karma. The former helps to compensate for the latter if it isn't high/low enough for the race in question.

Human-held provinces vary a bit, but having a few points of Diplomacy will usually open up a reduced-cost option for purchasing the land.

In regards to the Free Settlements when you try to negotiate with them they usually ask for like 450 gold or something like that. Having Diplomacy 1 opens an option that lets you pay half to the leader of them instead haha.

Exactly my experience. I usually couple a Scout with a Mage. Scout for early experience and diplomacy, Mage to absolute dominance when getting high level spells. Heck, even fireball can decimate a large crowd if your Mage has high spell skills. Sometimes I like to take the Necromancer skills, and if I am lucky enough to get an early Raise Ghost or Raise Vampire, well, my enemy can kiss goodbye to that shard.... I love those guys, they can destroy most units on their own (well, except dragons...).

I agree that Mages make good Heroes as they are my Fav. The main problem I have with them if any is that they are probably the hardest class to level up as Equipment does NOT really help them at all noticeably. For this reason they are my first char with Scout then Warrior as 2nd and 3rd ideally. Although which I get first usually depends on if there are elves in 2nd or 3rd ring that I can see or If I have a good Bow or First Strike weapon.

I just got my archer up to level 5 diplomacy, and it's awesome the things you can pull off.

I made a second scout and turned him into an adventurer -- the half-warrior scout class. I like archer better, but adventurer has its advantages. He can use heavy weapons and armor, and he can switch weapons with no action penalty so if anything closes on him he can pull out the hurt stick.

I agree that mages are the best at high levels, but they're so, so bad at low levels.

Like that? completed centaur quest with T1 spells and troops without casualties at 5th level. :)
http://img694.imageshack.us/img694/6041/screen8fb.jpg

Let me ask you this: Did you go back one turn systematically to get the increase in Magic or it was just luck? And do you recommend to use this technique? I usually go with what I get, but I am thinking to change my approach.