In which city is the alt upgrade more balanced?

Playing mainly as the Tower faction after the last expansion, I can highlight 2 of the most dangerous units from the alternative upgrade path: Stalkers and Matrons. On day 2, if you manage to get a squad of 30-40 Stalkers (depending on luck with heroes in the tavern) and a hero with Chaos magic (e.g., Synithar), you can defend any wood and ore mine. Thanks to their high initiative, they can turn invisible and be positioned so that they deliver an unexpected and unreturned blow on the last turn. If there are also wells on the map, you can capture all the mines in the first week. Artifacts that boost Knowledge and the Hall of Revelation in the castle are particularly important.
I almost always found the Meteor Shower spell on level 4 – it's incredibly effective. For Synithar, the enhanced Meteor Shower costs 14-18 mana (due to abilities).

I take Stalkers, Matrons, Blood Maidens, and Red Dragons into my army. I deploy the last two in battle only when things are really bad and the opponent has many immunities. But in 90% of cases, this wasn't necessary against neutral creatures. It's a bit more difficult against a real enemy; the main thing is to use magic to eliminate archers, mages, and the fastest and most initiative-driven units, but in principle, the alternative tier 2 units allow you to quickly win on medium and large maps.

I've looked at alternative upgrades for other factions – it's debatable. But the fact remains that you can find tactical combinations to defeat a specific opponent.