Yeah, considering a battery for my computer is $130, $400 dollars for a steady power supply like that doesn't seem out of line. I've seen reviews and they seem pretty promising. The only other thing is you need a seperate adaptor for each device. So a laptop needs a ~$100 cigarette adaptor to connect to it. $500 for the biggest power roll and adaptor is a pricy addition to a computer kit, but not out of line.