I started out purchasing the 300 series with the standard battery. Found it too inconvenient to have to keep recharging the device. So next I purchased the OBDII device. It works great but difficult to conceal so it's best for tracking only, not security. Since then I've purchased two hardwired devices and love them both. I've only had to contact SAM a few times, and each time it was either resolved thru AI or live chat. Good customer support so far.