I've been reading that thread for a long time because i'm really curious about those trucks. I skate mostly Thunders, and sometimes Indys but I never owned any Ace trucks. It seems that most of the people here have issues with the quality of manufacturing, whether it's the pivot cups, the kingpin or the bushings. Does anybody ride them without any issues and without having to change some parts?
Seen a lot of sets with zero issues skated to death from people I know and also seen one or two sets with minimal issues (which were warrantied and trucks replaced) from people who skate pretty hard on anything they ride, so I would be going with the majority in that they are perfectly fine with some very few exceptions, which were all covered under regular warranty anyway.
Maybe more so in the earlier days of the truck development, people might have a slightly more skewed version of "many trucks had issues" or similar thoughts, but I think everything has come a fair way since then.
Kingpins break, maybe more so hollow kingpins, especially on inverted trucks, of any brand I have seen.
Axles bend, also on any brand.
Other issues happen, yes on any and every brand...
The only other thing to say, from my own experience riding some of each - Classic and AF1 versions of different widths - is that they really do have a lot more turn than any other truck I had tried up to that point, as well as having the shortest wheelbase of any truck I had tried too, so those two things combined make Ace trucks very quick to turn and rather deep in the whole turn department.
I got used to this easily enough, but it was crazy how going back to any other truck on the same shape board felt like it just wasn't the same, even on my usual comfortable setups that I had not changed at all, so it made everything else feel like it didn't turn enough, or didn't turn fast enough, if that all makes sense.
Every set I have had were just plain stock, normal bushings, only the axle nuts swapped out on AF1 trucks, which is not a big thing, but I would say if you prefer a more solid or stiffer setup in the trucks and bushings department, get a set of the hard 94 duro bushings, or extra hard 99 duro bushings to go with them, just to have options, because these things felt way too loose for a number of people who have tried them, which did very easily put some people off too.
* Bushings are all white, so it is also very easy to mix and match without them seeming weird, eg blue top and orange bottom or some other colour combinations, but maybe just mark somewhere on them so you know what they are.
** Squeeze test with some pliers can also help to figure out which are which too.