There's a thread here recently about it. I know a few people who've picked it up, including myself and my buddy. Not sure in the life of the joints as I've only had it in a few weeks, but flexes great compared to my old short arms (was running fixed lowers and stock uppers). Install is simple enough, I suggest you massage your floor just a bit above the crossmember to get the upper link to slide in and out without dropping the crossmember
The threaded portion of the flex joints are welded on at an angle on purpose. This means you're stuck with their joints, or you have to have some custom made if it ever needs to be replaced. I'm not totally crazy about it, but so far hasn't given me any problems. Some people have had exhaust clearance issues with the lower passenger side link. Mine cleared just fine. Also seen some complaints about removing the whole cross member to get the upper link out, few whacks to the floor with a hammer solves that issue real quick as needabow mentioned. I went with the rock link because it had the highest clearance arms and cross member that I've seen out of all the three links out there, I'm super happy with my purchase.