Mack,
Whatever you do stay AS FAR AWAY from the oil less type as you can!! Your ears, and your neighbors will thank you! When looking at the unit ratings compare apples to apples. The higher the pressure the more capacity you will have to run air tools at a lower regulator pressure. This will also keep you working without the tank pressure falling below your regulator pressure as quickly. Its like a trailer get the biggest you can afford and you will not be sorry.
The more storage capacity that you have, you will be able to control the moisure better. This allows the hot compressed air time to cool and the moisture to condense in the tank. Otherwise the hot compressed air will carry the moisture out of the tank and through your air tools.
As for features:
- I would make sure it has a bleed valve. This is located at the compressor. It removes the pressure to allow easier starts (Unloaded starts, less amperage used)
- Cooling fins on the compressor discharge line.
- I prefer uprights for shops and garages. (Smaller Footprint)
- 208-240 VAC
- A single compressor should be fine, or step up to a multistage if you want to spend more.
- No smaller than a 60 gal tank.
- Oil sightglass on compressor should be standard.
- Harbor Freight sells 50' lengths of 5/8" Goodyear air hose. With one of the 20% off coupons you cannot get a better price for a good hose.
Depending on how your shop is wired, a plug is sufficient. The compressor does not have to be hard wired. That way if the air compressor is not in use, a small mig can use the same outlet. You would need to verify the amp rating for each device, to safely do that.
Good luck
Sean