TL;DR -- From this point forward if you are building *master* branch, use V3 board. 

Keyboard has been working almost flawlessly for the past 6 months. Battery has exceeded expectations and currently going on 118 days since last charge. I've only plugged it in a few times (less than 10) to flash new firmware, without charging it for any extended period of time.

No issues with key responsiveness / input delay. I can type at 120wpm without any skips. Unfortunately that's the upper limit of my typing speed so if anybody types faster, let me know!

2 minor issues that have come up:

• Keyboard pairing issue - Intermittently (once every 3-4 weeks) requires clearing nrf52 paired devices. I haven't had an issue with this since turning off FireVault on my mac. Nonetheless the combo key exists which makes this a 10 second process.
• Occasionally keys get stuck - Happens maybe once every 2-3 days and I end up typing ssssssssssssssome key. Easily fixed by restarting the keyboard. I suspect it's due to my soldering or the hole in the keyboard (where the cable use to be) allowing air in.

With those 2 issues in mind I've decided to upgrade to the recently released nrf52840 feather by Adafruit.

nrf52840 doesn't require a separate USB serial chip so it should result in even better power consumption! This also means we get the TX/RX pins back so we get enough pins to get RGB for the power LED back!