So y'all are saying Ace are more stable on center?
I would be more thinking it would be down to bushings and ankle strength, but everyone has their opinions.
Bushings can make or break a deal with regard to how a truck works. Mushy (or super soft) bushings just feel off, especially if you are not used to them, but more stable (eg harder) bushings will make any truck feel more stable, but it is also down to how much they are done up or how worn in they are too.
Ankle strength comes in to it when I see some people with completely loosey goosey / almost no bushings and still so balanced, whereas others might not even be able to skate medium loose trucks if they are not used to it.
Certain trucks are a lot easier to jump straight on and skate, but once bushings are worn in nicely, more often than not they will make for a more stable ride anyway, when compared to brand new first session, as I have found with stock bushings on both Ace trucks, Indy, Thunder and Venture, as well as others saying similar things about other brands of trucks too.
People who set up fresh trucks, then try to skate as usual right away often have more issues than if they took it easy and tried to wear in the bushings over a session or two, just rolling around and not going too big / too hard too soon. I have had to swap out / change over a number of bushings from people who just didn't give any wear in time and the bushings almost always tend to blow out, but most can still be recycled back into other setups and still work well enough.
On the debate about Ace or Indy being more stable on center, having ridden both, I can report that there is only one true answer: Theeve.
Stock bushings in those trucks are a lot harder than most, so it is only natural that they don't give as much right from go, as per a few sets I have experienced and happily passed on to others. Decent trucks, but just not what I wanted, but for those who are riding them and prefer a tighter truck, they are perfect.