I bought this set of Chameleon ColorTones pens about a month ago, and since then I've had the opportunity to use them quite a few times and get a good feel for how they work. Firstly, I'll tell you exactly what they do and the process of using them, which is unique in the marker world as far as I know. Another huge consideration is the cost, which is quite substantial.
The pens can be bought singular, in packs of 5, or the 22-pen deluxe set on Amazon & the Chameleon website. The cost is significant; each individual pen costs £4.99, the 5-pack £24.99, and the 22-pack a penny shy of a whopping £90. Are they worth this much? In my opinion, no, but we'll get to that later!
The pens do take a lot of getting used to, and I don't think I'm there yet. There are lots of tutorials on YouTube that make it look like a breeze, so maybe I just need more practice. The fact that you can't just pick out the shade you want and use it is the main thing making me stick with my Spectrum Noir. They are alcohol based, so you WILL have bleed through most types of paper, which is something to consider if you're thinking of using these in colouring books. Below are some pictures I've coloured with the markers. As you can see on the Unicorn hair and the ball pit, you can create some cool shiny effects with a little practice. They can come out streaky though, and it will definitely take a while to hone the technique it takes. My verdict? If you've got the money to spend and like to colour small areas (like card making), go for it. Otherwise, I advise you stick with regular alcohol markers so you can quickly pick out the shade you want, without spending lots of time waiting for Chameleon pens to infuse and then timing it just right to get that same colour.