Decent review of the SR Suntour Zeron coil fork.
100 grams lighter than the Z1 (if that's important to you) and has a really nice feel to it.
If your goal is giggles per dollar, it may make sense to opt for an inexpensive coil fork rather than cheap air...
nsmb.com
Looks decent overall, but only having two spring rates sounds a bit shit (Also sounds like different springs depending on travel? Not spacer-adjustable like the Z1...). I think for me though the advantage of a coil fork is being able to run bugger-all compression damping because the coil inherently gives the midstroke support I want. So I guess if you fell in the right weight-range of the two springs rate it'd probably be a okay buy.
Honestly though (and amusingly I find myself doing a mini-review of what I started this thread with...) - I'd probably still buy another Z1. That decision would be largely based on knowing that the damper and coil interact really nicely, and the chassis stiffness is excellent (No obvious fork bend under heavy braking for me anymore!). I bought the fork expecting it to feel like a cheapened off Fox 36 - but found no negatives (aside from the shitful QR axle that pokes out on a weird angle, though the purchase of an aftermarket bolt-in axle sorted that). Then I bought the coil conversion parts as a "cheap" way to dip my toes in the water with coil expecting it to clunk or squeak or feel cheap or bottom out or
something - but it just bloody works! (And works well)
I have a Grip2 damper spare I'll probably chuck in it at some point just to try, but I'm really not in any rush to do so. So yeah. Said it before, I'll say it again. Great fork, super-simple setup, highly recommend.