*phew*
Just done mission two of the campaign - must have spent at least four hours on it (!).
I fancy going through and completing, but does anyone know how long the campaign is? I've just done a quick search and I can't find too much info, but I just want an idea of how much time I'm committing here... :)
Thanks!

I'm not sure since I've only just got the game myself.
I'm @ level 3 three atm.
However, if you check your Heroes Of Might And Magic\MAPS directory. Your will find:
CAMP1.cmp
...
CAMP9.cmp
Therefore, I'm pretty sure there's 9 levels.
I'm more curious, if there's any difference between the heroes for the campaign?
I doubt it, but maybe the last levels or an epilogue?

I've finished the campaign. There are 8 levels.
The only big difference between the Lords seems to be that each doesn't have to fight himself in a 1v1 mission. So if you'd want to see all levels, you'd have to play the campaign 1.5x times.

I am actually on mission 5.
When I played HOMAM 2 years ago I often played too defensively which resulted in very long mission time or even defeat. Just note that the campaign is about early attacking (you get money and resources to attack, not to defend yourself), at least first few missions.
This should make things easier for you.
(the most boring thing is killing all the cpu heroes when cpu has last castle, almost no resources, no chance to win, but keeps buying new heroes and travelling - fleeing - all over the map)

I finished the game back in 1997. It was a crappy localized version (french) with text longer then text boxes could fit.
Both campaign can really mean 2 to 3h per map. Especially if it is the first time you play a map. I believe Roland's campaign is easier because of the dwarven alliance.
Some standalone maps are also very interesting and some of the can really be challenging.
In one word, it is a LONG game.

I just wanted to point out that OP was writing about the original HoMaM, not Succession Wars ;).

Good point.
Anyway I am soo great I was proposed betraying poor Roland. However I had to follow the story od MM6 (which I loved) so no.

Well, I didn't catch it at all :/
Anyway, if I remember well, the game the shorter and easier. Is it ?

The campaign doesn't have too many missions but they can sometimes take forever to finish...
As for it being simple - it's definitely less complex. A good introduction to the series, I'd say.