Well, my word is only so good here because I've only owned them a short time....I've had the rear ones on for 2 months and the front ones on for 2 weeks, so not a lot of time with these things. They look and feel very strong though. The customer service is awesome too. They delayed shipping for 5 days or so which I didn't even care about or bug them about and they sent me a 10% off coupon for my next order along with an apology note. I've heard from several other WJ owners that the arms were good quality, that's why I went with them. Haven't heard any feedback from a JK owner at all. One thing I noticed right away, it tightened up the rear axle a lot, I could tell on the first test drive. As far as the front axle, my steering feels way smoother, not that it bound before, but steering feels smoother, again I noticed that right away, I assume with the Johnny Joint flexing instead of a rubber bushing binding.
One negative thing I've noticed so far is that with a Johnny Joint, I do hear more noises, but I kinda expected that too. Another negative is they didn't come with instructions. I had to email them to see where they recommended putting the adjustable end. I found pictures online of them at the axle and at the frame. They told me that the adjustable end is usually at the frame. Also, the Johnny Joint sleeve length was shorter than my OEM sleeve so the new arms come with spacers to clear that up. Again, no instructions on where to put them. The rear was easy to figure out, but the front was quite confusing. Turned out the spacers went on the outboard side of the axle mount but the inboard side of the frame mount (or vice versa), it was the only way I could get them to fit, I had to stagger them. I went with the Tier 3 on front and rear.