I have the SPC's. My LCA bolts are seized solid, and I didn't feel like sawing them out, so since I needed new UCA's after my lift anyway, I went with the adjustable SPC's. I've been very happy. They've been on now for 50,000 miles and haven't budged or given any trouble. I grease them every other oil change, and check the torque at the same time. Around the time I put them on (late 2016), SPC raised the torque spec on the main adjustment bolt from ~120 ft-lbs to 150 ft-lbs. Apparently there were some problems with them working loose at the lower torque, but the increased spec seems to have fixed that. Mine have never loosened.
I do my own alignments (it's really pretty easy if you pay attention to details), so the extra complexity wasn't a problem. I set the caster on the high side to around 4 degrees and the truck drives like a dream. My KO2's have been on for 50,000 miles, still have 7/32 tread left, and are wearing perfectly evenly, so the alignment is working just fine.