Pluses first, cuz I'm a positive kinda guy. Basic function works fine. It's portable, immersible, and so far has stayed on when I put it on.BUTI had to get the charger replaced after about 3 months.The band split where rubber meets the LED window. Had to get that replaced after 6 months.The new charger needs help to get electricity to the cartridge. Cartridge snaps in place and stays there OK, but apparently not with enough force to make good electrical contact. As a workaround, I used folded up paper as a little wedge to force the cartridge onto the contacts more firmly. Also, I clean contacts with rubbing alcohol.Step count is greatly exaggerated, by as much as 20% sometimes.Lastly, the customer service flow needs work. The reps are courteous (as well as can be judged in email threads), but the process is a pain. Open a ticket, get an email, reply to email with picture (of a cartridge NOT charging or a broken wristband). If there was a way to upload the picture when first opening the ticket, I didn't see it. And furthermore - it's a USB charger! or It's a wristband! Just take my word for it and send a replacement. All these extra steps are costing them labor and me patience, with no value added. If I was asking for a new cartridge, maybe then some evidence is warranted.