Kinda summarize what others have went into length on....what do you get enjoyment out of more...shots or environment immersion? Wife and I played both when we first started playing a little heavily (before buying our AIQ), and we only got a couple of games on STh before ditching it. Reason we bought AIQ was because of the satisfaction of the shots. They all feel soooo good and buttery (if calibrated properly b/c that game is picky on having everything working as it should). We tried STh a couple of times afterwards and still couldnt get into it.
I think the "soul" people refer to is that it feels too...militaristic? Sure some callouts are snarky but nothing really sarcastic. All the cheers, insults, etc feel too straightforward. We recently started playing IMDN and have already implemented Satan's "oh no" callout into our own banter. My wife didnt think she'd like it more than AIQ, but now shes starting to debate. A little off topic with IMDN, but just a reference on what people prefer in game experience. IMDN in this case feels better to get enjoyment out of, but shots still dont feel as good as AIQ.