TK-3 на HeroesWorld

It seems there are no differences in combat.

There are some minor differences:
15% armor in SoD (the most important difference, in my opinion)
Antimagic - only earth in SoD, also a significant difference (increasing the role of earth)
Healing costs less but is weaker.
Hypnosis is weaker.

All of this is actively used in TC3 in ToE.

Regarding prices, there are big differences. In SoD, it's easier to buy units than in ToE, even though there are more castles. (exception - tower, where only genies are cheaper by 4000, and nagas are more expensive by 4, and mages by 3 thousand)