Is there any cutoff for the CAT4101s? That is one thing about the Meanwells I don't like, they cut out at about 30% which is still pretty bright when driven at 800ma max.
Also I wonder about moonlight support. Something like 2-3 LEDs running off one channel fully dimmable would be nice.
There's no abrupt cut-off with the CAT 4101's. They can be made to dim to a fraction of 1%, provided the PWM signal frequency has been set low enough. 150Hz seems to be that magic number. It's too bad only 2 output pins on the arduino can be configured to PWM with a frequency that low.