Let me start by saying this filament is a game-changer for anyone who loves vibrant, eye-catching prints. The color transition every 8-10 meters creates stunning gradient effects that make even simple prints look like works of art.

The matte finish is what really sets this apart from other rainbow filaments I've tried. It gives prints a sophisticated, non-reflective surface that makes the color changes pop even more. I printed some fidget toys as test pieces, and the results were jaw-dropping.

Printing was surprisingly easy - I used generic PLA settings on my Bambu P1S (190-220°C nozzle, 50-60°C bed) and got perfect results right out of the gate. No clogging, excellent bed adhesion, and minimal stringing even at higher speeds.

The cardboard spool is eco-friendly but does feel a bit cheap compared to plastic ones. However, it worked fine in my AMS system without any feeding issues. The included zipper storage bag with desiccant is a nice touch for keeping moisture out.

My only minor complaint is that you need fairly large prints (100g+) to fully appreciate the color transitions. Smaller prints might not show off the rainbow effect as dramatically.

At around $20/kg (with discounts), it's pricier than basic PLA but absolutely worth it for special projects where you want that wow factor. The quality rivals filaments costing twice as much.

Final verdict? If you're looking to add some magic to your prints without sacrificing printability, this filament delivers in spades. I've already ordered two more colors from Gratkit's matte series!