Personally, I like an air/oil microdrop lubricator on an unenclosed machine because flood coolant can get you pretty wet if the coolant gets drawn up the cutter onto the collet and flung away. You may find you actually need a spray of coolant to get the chips out of the cut zone and this gets really messy unless your machine is built into a cabinet, and all the screws protected, etc, (which they should be anyways, I guess).
You also need a coolant collection tray and settling tank. If your machining activities are infrequent, the coolant may not keep fresh smelling all that long (considering the expense of it).
FYI, the Trico microdrop air mist unit allows you to get the chips blown out of the cut zone immediately, and uses an incredibly small amount of vegetable oil lube per hour. The chips are dry, too and no fogging or fumes (WD40 does bug my sinuses after prolonged exposure).
I know it all costs $$$ to set up
