I’ve currently two pairs of coil Helms; the older set has been on a 29er steel hardtail for over a year and has been well used in the Scottish mountains. Best fork I’ve ever used, which is a strong recommendation as their main comparison is with an older coil Lyric with Mission control damping.
These are better, best described as both supremely plush and ‘calm’.
The newer set completed an 8 days’ of riding Alps trip a fortnight ago, fitted to a Cotic Flare Max. Again, simply superb and both have been utterly reliable. I’ve a pal with two more pairs, again coils and again, 100% perfect reliability so far and when opened up, they’re all spotless inside. Travel adjust, while an internal job, is quite straightforward.
I’ve not ridden the airs but understand that they ride almost as well as the coils.