The PVA kits work well, but the Primal Rights ones are the de-facto standard with AICS magazines because they're more readily available than the PVA kit. For AW magazines I prefer the HRD Gear spacer kit since it's machined instead of printed similar to the PVA one.
I've found in my Nucleus action, though, I've had almost the best luck just using an unmodified (no spacer) ARC magazine. I've used them in 2 matches and plenty of practice sessions without any issues thus far.
For standard AICS magazines I use no-binder plate Accurate Mags with a custom kit I'm developing. It's designed to not require an extra spring like all the other kits, you can re-use the original leaf spring from your AICS/Accurate Mag if you remove it from the stock follower (just a pair of rivets that can be replaced with $0.50 of screws and bolts if you remove the spacer later). This should allow for a cheaper overall kit since it's less stuff to ship out (though I've also been testing it with replacement springs).