I've no affiliation whatsoever with Overkill Solar and the only reason I purchased them was following Will's suggestion in one of his videos. So while I may suggest in my limited opinion as a beginner they are fantastic with a huge amount of data that is available and also programmable/changeable with limited pc/IT skills.....I love them for their simplicity.
They are not the cheapest by far but do allow the user to control a considerable amount of cell autonomy over some of the cheaper BMS's.
Also I purchased them as I'm new to this battery DIY building (but not new to R&D and building). But because Will stated they are a very good make and build and the company undergoes testing of their BMS's and supplies test sheets to collate their test results, (which are then supplied with each BMS), hence their slightly dearer costs to reflect the companies input.
Also I've had a few emails to and from from Overkill customer support who were extremely helpful and reasonably quick with responses.
Using my Victron 500a shunt for the capacity testing and taking readings, I've played around with a few iterations of cell capacity percentage figures, (including those supplied when I asked Overkill solar customer service ) for the EVE cells. These readings were different to those supplied in the BMS program. And I've since changed them again going by the Shunt's accuracy.
So here's a screenshot of the final iteration of voltage readings I've inputted into my BMS.
These voltage readings appear to reflect a fairly accurate cell capacity percentage.
While I'm not a guru and still learning this fascinating discipline, it's a reasonably accurate reflection on the EVE 280ah Prismatic LiFePO4 cells capacity voltages. Over time I will be keeping an eye on the bank and may update the readings again but the changes won't be substantial.