I received a Teensy 3.6 this week to replace the 3.2 I was using. I have to say, Paul Stroffregen has done an amazing job again! 

The package, is maybe a little too big, as the board has a micro SD slot embedded in it and many IO. But here are some comparison from the website OpenAudio.

It's not on this list, but the Teensy 3.6 can be overclocked at 240MHz which makes it two and half times faster than the Teensy 3.2 I was using. I can easily double the number of LED or read twice as many pixels and still be more reactive! :-)