When you are considering a surge protector you are basically looking at protection from lightning spikes on the electrical power that comes in to your house. These surge protectors use Transorbs to clamp the voltage to any electrical appliance that is plugged into the surge protector at a certain value, usually 10-15 volts above the normal value. Transorbs are rated on how much energy they can handle. You will find that the more expensive surge protectors can handle more energy, and that energy rating is listed in Joules. So if you pick a surge protector that has only a 1000 joules or less of protection, you are gambling that the power lines that supply your house (or business) will never see a serious voltage spike due to lightning. If you live in Alaska, or the West Coast, that is probably sufficient protection. But if you live in Colorado or any of the midwest states that see most of the lightning activity (or Florida), then you better get a much healthier surge protection. 2500-4000 joules is a much better rating for those states. If you scrimp on the protection, you are taking a big chance. Tthe power companies have some protection to limit the overvoltages that occur when lightning strikes a power line, but the closer the lightning attachment point to the power lines to your house or business, the more chance that serious voltage spikes will get into electrical appliances in your house.
So make your choice, are you going to gamble that a lightning strike will damage your system or will you pay what is necessary to protect it?