Great team, friendly people. The energy storage industry is in a very interesting place right now. The product is unique and challenging, work is never dull.
Cons
Work load ramps up and down, slow times can be a bit of a bummer
You get to work on a great deal of new projects and ideas as different iterations are tested. Employees share a drive to make things work quickly. Lots of fun working at a "startup pace" if it's something you like.
Cons
Poor decision making (both engineering and business) due to concentration of decision making in the hands of those who spoke the most rather than the hired experts. Lots of turnover while I was there.