Stila $22.00 full size (I just have a sample size)
NYX has a tiny bit more pink to it and it overall a lighter red, whereas Stila is a darker true red. Stila also has much more pigmentation (as you can see in the side-by-side swatch picture). The Stila one is a true matte lipstick product, no shine whatsoever, whereas the NYX one takes awhile to set and will have a bit of shine until that point. The swatch on my lips is right after application, so you can tell that it still has a bi of shine and moisture in it.
NYX will last you about 3 hours before you will need a touch-up, while Stila will do just fine for 6-8 and it really only starts to fade on the inner parts of the lip and it's not super noticeable because it can leave a stain behind too. The Stila product is a truly a long-wearing lip product and once it has set on your lips for awhile, it's pretty transfer resistant. The NYX one continues to transfer even after it has set for a long time. The NYX isn't necessarily advertised as being long-wearing so it doesn't last much longer than any other lipstick.
Feeling on the lips:
I can't stand the Stila one for more than 3 hours on the lips without wanting to take it off, apply some lip balm, let my lips relax, then reapply it. NYX also becomes drying if you just directly reapply it on top of the worn lip cream, but neither of them get chunky, goopy, or strange if you just directly reapply them on top of the worn product. However, I don't find NYX to be as drying feeling, like the Stila one. The NYX product is a creamy consistency, which I believe helps it feel more comfortable on the lips, with a slight bit more moisture. The Stila one dries down to be a long-wearing lipstick product, so it will of course have less moisture in there. Keep in mind however, I am a lip balm addict, I always want moisture on my lips, so you may or may not feel the same way about these matte lip products as I do.
Overall, Stila's Stay All Day Liquid Lipstick is a great long-wearing lip product if you can deal with its lack of moisture. I wouldn't consider NYX's Soft Matte Lip Creams to be a dupe because they really don't have the pigmentation or wear-time Stila features. They are still both really nice red lip options, but it just depends on your budget and what you really need out of your red lip product.
Thanks for reading!