I've owned 3 of these for between 3 - 5 years and use them to ride out short outages and provide additional smoothing for any power spikes to protect computer equipment and entertainment center. I've recently purchased a fourth for an additional home office. In the time I've owned them I've had to replace two sets of batteries, but the units themselves have continued to perform without faults. As others have mentioned, the units can be quite noisy when initially charging or recharging after an outage, and charging can take quite a long time (24 hours or longer if fully drained). If noise is a concern you can consider a lower power fan-less...view more