Guess I'm a little late to the party but I'll throw my 2 cents in.
I've had my MC control arms something like 10 years now, basically one of the early adopters when MC was the new kid on the block. My Jeep rode like shit before the MC arms and Pro Comp shocks, rode like shit after the MC arms with same Pro Comp shocks. Only issue I've had with the joints was on one of the rear control arms years ago. I had welded one of the axle brackets on a tad crooked, so the joints were always misaligned. That killed the joint pretty quick. Fixed the bracket, replaced the joints, no issues since. If they had been JJs it wouldn't have mattered if the bracket was crooked.
MC front track bar I got for free back in the day to test. Have had to replace the rod end once.
Currently installing MC overline fenders. Not my first choice in looks, but they are decently priced, easy to install, and don't have to fuck around with the under-hood shit. I'd prefer the GenRight fenders, but for how much they cost the don't even include inner fenders, and the inner fenders you do buy are generic, so you have to fuck around with under-hood shit.
The marketing wank is very strong with Metal Cloak, I can see why it's a turn off for many. Looking back, I wish I hadn't gone with MC for suspension stuff, especially since at the time they only had single adjustable arms, which SUCK BALLS. At the moment though everything still works, and there are better ways to spend my money than replacing everything for no real benefit.