Is mass thor attack good?
If your enemy scouted you: No.
If your enemy did not scout you and you’re aggressive: Yes.
I am not a Terran player, though, I am a Protoss who lost to such strategy.
Depends. In the lower leagues it will do the trick. The moment you hit plat or above people put early pressure and scout, so you will probably die before you get the thors out. Starcraft II is more then making one unit and try to win the game with it.
If you scout it build mass immortals they wreck thors, especially as the upgrades go higher.
Immortals are ok disruptors are why there completely unviable along with hellbats there the type of unit that would be banned in other games like pokemon due to removing too many options and making for stale metas.
Literally awful in TvT (tanks), TvZ (blinding cloud and neural parasite) and TvP (immortals).
They are alright versus mass carrier sometimes and broodlords. In lower leagues you can beat some protoss with massing thors. There is a TvP meme which sounds like Thor gud unit
. Against zerg i would not recommend it cause they will go for those super long ranged lurkers. Against terran i dont think they do well honestly, battlecruisers liberators siege tanks, hell almost anything the terran makes that isnt hellions counters thors. But if you surprise him with a thor drop then perhaps you can do it.