Mark - After 36+ years in the flooring business and knowing how you USE a shop I'd leave it natural.
If you want to keep it looking nice with all the money you'll save on applying a formal finish go out and buy a 17" commercial polisher/buffer, scotchbrite pads, floor squeegee, and a ph neutral cleaner. Deep clean it once or twice a year and in between you can damp mop and spray buff it with a low build sealer/polish.
Find a good janitorial supply house in your area and go talk with them about equipment and products.
Just damp mopping and spray buffing with the buffer will result in a clean looking floor with a nice natural patina.
With any formal finish I've seen (residential & commercial) you'll have staining, chipping, scratching, lifting due to contamination or moisture, and burning from welding. In your case you have an existing slab and contamination, likely no company with experience will warranty the coating......maybe if the acid wash and bead-blast it first. They look nice but for how long and how much effort.
Besides I've never paid attention to the floors in your pictures and I was in the business.
Here's a site for quick online reference (No experience with them)
http://www.globalindustrial.com/g/ja...lFloorMachines