I was just gifted one this past xmas. I'm not a pro like most of you guys -- haven't yet done a real mash, but I have done maybe 100 kits, extracts and my own recipes.
I'm really enjoying playing with the BEERmkr thus far. Haven't broken it, so that's a good thing.
I have managed to break the picnic tap that comes with their dispenser. The top lever has some thin vulnerable plastic tabs that bend or sheer. As the company went with a non-common nipple size (1/8 rather than the more common 3/16-1/4"), it took a while for me to realize the same company makes both - so I could unscrew the top valve assembly from a 1/4" one and thread it on to the 1/8" nipple body. Beer flow restored.
Sure, it's a bit pricey. The capitalization for the engineering probably wasn't free -- even if the founders laid the groundwork for the controllers. But they seem to continue with some firmware updates.
Where they could really shine would be to open up the software a bit. Presently, both the BEERmkr and the phone app have to call home to interact. That requires an internet connection for both -- so those of us who sometimes find ourselves vacationing off-grid would be SOL for a batch. Will they evolve the software to work solely on a LAN, perhaps with the phone app or a desktop app to hold recipe libraries and manage the BEERmkr device locally remains to be seen.
Thus far (only two batches in), it's a fun small-batch solution.