BitAxe is great! It's fully open source hardware and software. Two guys from my local BitDevs meetup made it happen. Skot9000 started the project and designed the hardware. Johnny9 backwards engineered the firmware.

It's super easy to set up. You plug it in and connect to the wifi network displayed on the screen. Configure it with your wifi credentials and reboot the bitaxe. Open a browser on your local network and browse to the IP displayed on the screen. Configure your mining pool credentials, save. You might need to reboot it again. Congrats! You are hashing.

The thing that sets this project apart from similar efforts is the hash efficiency. A nerdminer does CPU mining on an ESP32. BitAxe uses an individual ASIC chip from an S19, I think. So you are getting industrial strength hash efficiency in an adorable desk toy format. It's like a cool knick knack that puts out 500 GH/s. I put mine on a shelf with a bunch of bitcoin books and a laptop full node. When it is quiet I can hear it 'breathe' as the fan alternates speeds to maintain target temp on the chip.

In general, mining profitability will almost always be lower than just buying BTC on the spot market. This starts to change if you operate at a very large scale or have access to free or subsidized hardware or electricity. BitAxe is at the extreme end of unprofitability. Due to the high relative cost of the hardware you might have to mine continuously for a century to break even.

Skot is working on a hex board that will fit 6 ASIC chips. It will definitely help with cost efficiency. If you are interested in this stuff definitely check out the Open Source Miners United initiative.