Hi @bsanchez,
There is a good response on this topic from @mwood here. I have used both in the classroom. I agree that the LEDs on the Circuit Playground are brighter and produce light in the rainbow of colors. The kids really enjoy the “light show” they create. You can also do more with sound on the Circuit Playground and Code.org interface. The microbit has the ability to give the text output on the pixel display. Both are a good physical computing experience. This article looks to provide a good overview of the Circuit Playground and other boards. This article gives an overview of the microbit.
~Michelle