1. You take fewer losses with Hack against neutrals.

That's what I tried to prove some time ago – in certain types of battles, there's less retaliation with a heavily boosted attack than defense, but these are considered easy fights and therefore don't really matter. Try to beat, for example, 24 Vyv monarchs with Crack level 7 (1 hydra, 29 lizards, 40 gnolls, 3 gorgons, 25 upgraded flies). Tazar did it (ProtosArchon-Chemist).

2. Hack has a higher chance of getting armor than Tazar has of getting offense.

According to the manual, it's the opposite – 30% barbarians, 25% beasts. Maybe certain heroes differ...

3. Hack gets better magic skills than Tazar. You almost always get earth and air with Hack, but the same can't be said about Tazar.

+1

4. Yes, but in all previous battles, Tazar will likely have *much* fewer losses.

Added after 30 minutes

According to the manual, it's the opposite – 30% barbarians, 25% beasts. Maybe certain heroes differ...

Tested – 10 tries, up to level 8 – Crack had a 50% chance of getting Armorer and a 70% chance of *not* getting crap as the 2nd upgrade; Tazar – 70% (offense), 80% (no garbage creature).