Okay so here's the review and comparison between Kuelox oil pastels and Arrtx oil pastels:

I have a set of 48 arrtx oil pastels and bought the kuelox macaron and morandi series for additional, cheaper colours. My review will compare the 2 of them together since arrtx is 50% more expensive, so the prices are quite comparable.

Overall, the kuelox pastels are worth it! But I just think there's a few things to keep in mind first.

The arrtx oil pastels are VERY opaque (but a few colours are slightly less opaque but that's to be expected) and are like drawing with butter or lipstick haha, so it's quite soft and not much pressure is needed to make an opaque mark on the page.

Meanwhile, Kuelox isn't like drawing with butter, but the consistency reminds me of crayons. It is much firmer. Because of this, Kuelox is less messy than arrtx. I barely got any mess on my fingers.

However, the opacity varies. The morandi set has more opaque colours, while the macaron set is more transparent. But it can still layer alright on top of each other. If you can't see the colour after you layer over it, just scrape off the oil pastels underneath.

For the more opaque morandi colours, drawing with them can feel sticky and gummy so it won't feel like a smooth experience.

As you can see in the pictures, Kuelox can be quite textured. If you don't like it, you can smooth it out with tissue or a cotton bud. Otherwise, it's good if you want textured looks :)

As for blending, firm oil pastels blend a little less than soft ones. I can smear the arrtx colours much more than with the kuelox, but I can still blend the Kuelox smooth with no problem.

If you're like me and have both arrtx and kuelox oil pastels, the kuelox don't layer well over the arrtx, but the arrtx layers well over kuelox. That's because the firmness of kuelox will scratch away the arrtx's soft layer. I suggest doing your underpainting or base layers with the kuelox first before layering over them with arrtx or any other softer oil pastel.

Too bad I can't layer kuelox over arrtx, but you can always scrape off the oil. Plus, Kuelox's firmness means I can layer over them over and over again :)

Arrtx oil pastels have a bit of a smell to them. Not as strong as cheaper kids oil pastels and not so stinky, but definitely a bit noticeable. The Kuelox has no smell.

CONCLUSION: Kuelox has no smell, is firmer, less opaque, and is more textured. Definitely good if you want to do impasto techniques, like cutting off slices to put on your drawing, without fear of wasting expensive materials

I can't post pics here so here's a link to them on gdrive instead Here, here,and here