I'm getting ready to buy a new air compressor. I have a choice between a 25 gallon, 6HP direct drive, oil free model and a 25 gal., 6HP oil lubricated model. Same manufacturer, same 135 psi max., same CFM rating. The oil lubed model costs $35 more. So guys, what's the pros and cons of oil-lubed vs. oil-free air compressors?