Coil forks. Yay or nay?!

I think that they will work fine with coil shocks.

If you try to mix a coil fork with an air shock, I think the fork will always dive more than the shock, making the bike feel awkward. But that's just a guy that never tried a coil fork talking...

It would be nice to hear from coil users!

Coils? What's that? My elastomers are working just fine.

I'd be interested in the cross-contamination of air and coil.

I've only run coil sprung DH forks, never on my AM bike. I am more intrigued by coil rear shocks as I have blown up far too many air shocks...never an air fork.

Coil fork/coil shock works real nice. Cant say ive ever ridden air shock/coil fork, but coil shock/air fork just was'nt pleasant for me, and that was with high end stuff (CCDB and Lyrik RC2L) on my SB66. Had a 2010 Lapierre Froggy 318 with Domain 318 forks and Fox Van R shock and even compared to the Lyrik RC2L and Vivid Air R2C I have now, that was hands down the best suspension set up i had. I never touched the fork, don't even know what spring was in it if I'm honest, but I genuinely cant ever remember bottoming it out, yet it's the only fork never to give me hand/arm pump, and the rear end too was ridiculously supple. Honestly, I regret ever selling that bike, just wish I'd managed to get hold of a large instead of a medium. If the progression is equal between coil fork and coil shock and the bottom out is fairly difficult to achieve, then I'd 100% have coil front and rear again. It just works. (all this is IMO, I'm not saying that anyone else is wrong in anything they might think )

Its definitely a preference thing. Ive tried both and have had at some point air/air, coil/coil or air/coil. I havent tried a coil front air rear setup but i dont really think i need to at this point.

The coil sprung forks ive owned have all had their pluses and minuses (marz shiver, boxxer team, some experience with an older fox 40) but ive ended up back on air every time. (currently bos deville fcv and boxxer wc) That goes more to what I prefer sensation wise than to any downfall of a fork. Ive always found coil forks to be very supple, good at tracking the ground, good at dealing with arm pump etc but for me, the air works better. I would probably have a slightly different opinion if i rode drastically different terrain than i do, (home trails are lots of high speed, semi smooth trails rather than straight chunder all the time) so for my style and terrain, the way the stroke of the air fork can be tuned is far more important to me than how supple or plush it is. Coil forks tend to feel very soft and sluggish to me and they blow through their travel easier. This is of course a positive if your seeking that really plush rock gobbling feeling. In the front im more concerned with the fork being supple enough to track the ground while being stiff enough to hold itself up and preserve the geometry of the bike through repeated impacts at high speeds. A well tuned air fork just gives me the feeling im looking for from the front of the bike but again, thats based on my riding position, riding style and sensitivity to midstroke support.

I use a coil rear shock 100% of the time though because in the rear of the bike i want that plush stuck to the ground feeling, im less concerned with more frequent bottom out from the rear of the bike because my legs are alot stronger than my arms and much better at dealing with that sort of impact. Also, the stability of the bike that comes from the geometry isn't hampered by the rear bottoming as much as the front.

try a couple of options if you have the opportunity but also recognize that if you need to make a sight unseen decision, most of the high end stuff these days is pretty sweet regardless of coil or air.

^^This^^

My main concer with coil forks is that they may dive way more than air forks, increasing the chances of going OTB on steep sections.

But of course they are unbeatable in terms of eliminating arm pump...

Well I have never tried coil fork, but I have tested a few different configuration on the same fork (stock pike, pike with fast suspension cartridge, and now pike with fast cartridge and "luftkappe" style air ). For the rear shock however I'm pretty much sold on the coil shock (moto c2r on a nomad).

And this very subject has been discussed quite a few time on french forums with guys like novyparts (the french vorsprung). According to him, coil doesn't suit short/mid travel forks because there isn't enough travel to absorb the hit. So, especially if you are an agressive rider, you end up with a fork either too hard, or too easy to bottom out.
My personal experience tend to concur. With a coil shock, it really depends on your bike's kinematic but you can get the suppleness and support of the coil without bottoming too easily. On a fork however, I really believe an extended negative air chamber is good way to go. You get a coil like suppleness with good bottom out control (so it is very sensitive and allows for a lot of grip, but as soon as you go deeper in the travel it can feel pretty hard).

On paper a coil spring with an air chamber to control bottom out could be quite awesome, but I'm not sure of how it would ride.

Anyway just my 2 cents and ultimately, just like it is for the shocks, I believe it's all about rider preferences, riding style and terrain.