Had some 351 coils on a bike for about a year. Essentially the same fork just with coil sprung rather than air.
Anyway, the fork was excellent. OK, not the lightest fork out there for its travel by some way (Air sprung is about 1/2 lb lighter, so usefully so) but very stiff for a QR fork, damping was WAY better than anything else even remotely close in price (I did buy mine for £160 brand new though!) as it's essentially the same Motion Control as on Pikes/Rebas/Revelations just without the adjustable compression damping threshold, but would you use it if you had it even? I found the damping just about spot on anyway, there's lots of rebound adjustment to be had too, and a lockout if you want/need/use it at all…
FWIW I'm more of a fan of the Rockshox Solo Air springs than I am their Dual Air. Simple reason is they're easy to setup! Yes, with a Dual Air you can faff about, and get different characteristics. But the Solo Air system matches the positive and negative pressures exactly, just as PeterPoddy said, meaning you automatically get the best setup IMO.