The other thing to consider is the power requirement for a dehydrator.
If you need to dry a lot of food and hurry it up, then you will seek the higher-powered machines, typically well in excess of 1000 watts. However, you don't get something for nothing, and your electricity bill will be high for a lot of use. The 500-watt machines are obviously more economical, but much slower.
I have free AC power from a photovoltaic system, but only if I keep the dehydrator in the 500-watt range. If the dehydrator is over 1000 watts, the voltage is insufficient or else fuses blow.