I have the Core Tier 2 arms all around with Tier 3 track bars. They are solid/substantial, but I'll admit that mine sees light trails at most, so I'm not stressing them much. That said, based on what I recall from my engineering classes, there are a lot of other components in the suspension system that are going to break before these arms do.
Cheaper arms have a rubber bushing at both ends (like your factory ones). A bushing at both ends requires the arm itself to twist under load, just like the factory ones do. A round arm, however, had very little flex, which means that the bushing instead transfer all that twisting motion to your mounting brackets, and they won't take it for long. An articulating joint at one (or both) ends, however, spices that problem since the joint now handles the flex, say least until you are out of movement, then it again goes to the bracket.
I did a lot of searching before I settled on Core, since I wanted US made, high quality, and Johnny joints, but without paying a premium for a name. I'm not saying the others aren't legitimately better, just that I couldn't justify the premium for my use.
Hope that helps!
