I was surprised how light the battery was - ~15lb lighter than a lead acid battery I usually get for my mower. The construction felt rather cheap, but so far the battery starts the mower without a problem. After 2 weeks and 2 mows, the % charge is still ~95%.
Overall this is an amazing product compared to a lead acid battery (if it lasts). The construction may be cheap and the app is a bit sketchy, but the performance is there. 4 stars - will have to see how it performs in the next year or two and re-evaluate.