My Pro Micro's been a lot of trouble. Its
flaky powering my AT off a USB hub while I've never had trouble with any of the Teenies I've used in that rôle. And getting a firmware onto it in the first place is a nightmare I don't want to have to ever repeat. Lesson learned. I'll gladly pay the Teensy price!
But what you should really* do is use the ATmega chip directly. All the cool kids are doing that on their PCBs. Way cheaper, way smaller, way more elegant. Don't you even get Teensy Loader compatibility if you buy
the chips from PJRC?
*No. What you should really, really do is use an ARM processor. But that requires building your own software too. AVR / ATmega is pure
shit. Horrible high power consumption, pathetic performance, and so little RAM to play with in this day and age it was surely made by a sadist! Even keyboard scancode lookup tables are huge compared to its resources. What hope have we to ever drive Bluetooth from a single chip! But like all of us here, I love the software that runs on ATmega, so I use it incessantly too! PJRC pretty much created this space, and did so around ATmega. We really need to break out of it sometime.