What is your favorite installment in the Heroes series? Auto-translated

The best one is definitely the fifth installment! The best ideas from the fifth game are initiative and the Action Points system, unique skills for each faction, the best balance, dividing spells according to their function into schools, and the hero's participation in battle (although this is an overdoing in the fourth game), and the absence of unnecessary skills and spells.
As for the third game, it's generally good, but there is some monotony. All factions are similar, except for the Necromancers; half of the spells are unnecessary, as are some of the skills. For example, I never take Training (a negligible bonus to movement), Spell Exchange, Scouting, Ballistics, and other similar skills (spending an entire slot for a useless ballista, catapult, which you rarely use, or a tent, which still doesn't resurrect), Eagle Eye (absolutely useless), Mysticism (without wells, no amount of Mysticism will help!!!), and I almost always take Wisdom, Logistics, Earth, Armor, etc. And the balance is terrible. Why are the Black Dragons and Archangels always the strongest? And Hydras, Devils, and Bone Dragons are noticeably weaker.
The fourth game also has some good ideas, such as simultaneous attacks, which greatly complicate the game, making a flawless Walkthrough almost impossible. But in the fourth game, in my opinion, the graphics are the worst; they tire your eyes faster than in the third and second games.

I voted for 5 and 2. In my opinion, these are the best installments in the entire series.

3 and 5. 3 – because it’s a classic and has a user-friendly editor. 5 – because of its excellent storyline, graphics (HD, I played 5 first, then 3, and I didn’t immediately notice that the graphics in 3 were 2D), the ability to create videos (unfortunately, I don’t know scripting, but I still do), and finally, the editor offers virtually unlimited possibilities.