If your business needs to get some air compressors, obviously the ideal scenario would be to have a few different types available for all your needs. But for most businesses, you've got to find one, maybe two compressor types that will allow you to do as much as possible. Power and cost obviously play a role in what you choose, but there are additional issues that you need to look at to ensure you don't wind up in a bind when you get the compressor.
You'll have a choice between gas- or diesel-powered machines and electric-powered machines. A plus for gas/diesel machines is that they don't have to be tethered to anything like an electric machine does; even if your electric compressor uses a battery, that battery has to be recharged, meaning you have to plug the machine in for a while and limit its range.
A plus for electric machines, though, is that you don't have to worry about storing volatile fuel at your worksite. While there are ways to safely store the fuel, it's always safer not to have it on your property if you can avoid it.
Keep in mind, too, that gas-powered machines shouldn't really be used in enclosed spaces. There is a carbon monoxide risk if you do use it somewhere that's closed up.
You've got three choices here as well: portable, non-portable, and vehicle-mounted. If you want a small compressor that you can carry, obviously a portable version would be the one you'd want. But there are also towable compressors that are larger. The drawback to these is that you need a vehicle that can tow trailers and that has a hitch that will work with the compressor. Vehicle-mounted compressors eliminate the towing requirement but do take up space in the back of a truck, and they pretty much make that truck dedicated to carrying the compressor around and not much else, depending on how large the compressor is.
Compressors can overheat as they're being used, so they need to have a built-in cooling system. Air and water are two common cooling types. The cost of the extra water that you'll need or the extra fuel to power the air cooling can make a difference. You may also find that water-cooled compressors offer more cooling (and thus use more power and water) than is necessary for the jobs you'll be doing.
Air compressor dealers can help you choose the right style of compressor for your business and help you figure out additional things like fuel storage. Don't risk throwing money away on the wrong piece of machinery.