Depends what you are going after. If you want to apply product with a lot of water volume, use a Fieldjet. If you want to cover a wide area without a lot of volume, use a Boomjet. We have both on our sprayers and use each one for different things.
The Fieldjet, also sometimes known as a Floodjet, is found here:
http://www.teejet.com/english/home/products/spray-products/boomless-spray-nozzles/fieldjet--boomless-nozzles.aspx. We use this to apply product in upwards of 80 gallons an acre, especially slurry type products that normally would otherwise clog normal nozzles.
The Boomjet is found here:
http://www.teejet.com/english/home/products/spray-products/boomless-spray-nozzles/5880-boomjet--boomless-nozzles.aspx. We use this to apply insecticides in broadcast applications. Typically applied using as little as 15 gallons per acre, we can apply our wall-to-wall insecticide applications in a matter of hours.