As part of a 3D-printing company that uses FDM and STL to produce products we sell, I go through plenty of filament. Atomic has become my go-to for most filaments. There are many suppliers to chose from these days, but I usually check Atomic first. Not because they're the least expensive (they're competitive, but usually slightly higher than the cheapest), but because I can count on their quality and their customer service. Of dozens of rolls of Atomic filament consumed in the last year alone, I've had exactly one which didn't perform as expected. Atomic not only stood by the product, they went the extra mile to make sure I was satisfied with the resolution and to make sure that they truly understood what happened and how to avoid a recurrence. (Turned out to be some form of technical production problem).
I not only highly recommend this product in particular, but I cannot say enough good things about Atomic products and Atomic as a company to do business with.
Really appreciate the kind words. We work very hard to make the best!