I recently visited a bait and tackle shop in Lighthouse Pt, FLA called Custom Rod and Reel. This place was a Swordfishing mecca with tons of gear, like electric reels, all kinds of deep drop weight, various UW lights, etc etc..
I spoke to the owner, Tom Greene, who seemed to be one of the most knowledgeable guys on the planet about this type of fishing. He believes the Swords down in FLA are the same as those up by us.
As Marc mentioned, they hang deep during the day in water 1500+ feet and feed on bottom bait, like squid, crustaceans, etc etc... The ones they do catch are generally very large.
With braided line, electric reels and deep drop weights, this type of fishing has become fairly common. In fact he just invented a device that attaches to an electric drill that hooks up to your large Penn or Shimano 80W so you can check your bait very quickly. Cranking it by hand seems nearly impossible after a few times.