I don’t know about best, but my two coolest are a tie.

Noctigon k9.3 looks wicked from the front, and deep red complements the sst-20 well. My most common setting is mostly red with just a bit of white for a pinkish nighttime beam.

The other is the Fireflies t9r. It throws and holds its heat well for its weight. The ice-cream shape is actually smart, much more packable than the typical plunger shape.