It can actually look better than dyesub PBT given the right background since the fidelity is higher. Depending on the printer they use, some are close to 6000DPI. The way QWERKeys/Sleabo does it doesn't result in the best look on dark keys (wish I knew that before), but there are ways of making it look good even on dark caps.
It's also quick, easy, and fairly cheap to do, probably cheaper than their laser:
Odds are they just have a little jig they drop the set in, an acrylic/wood/metal/whatever mask they set on top of that, then they just print the full image.
It's cool, but I really wish they would work on getting a better cap supplier before doing gimmicky stuff like that. They're so bad that I'd rather have OEM caps than WASD caps.