There are lots of concrete sealers, and may seem overwhelming.  Which to use?  While this is not a perfect answer, it's a good answer:

Concrete Countertops, Furniture, Sinks:

  • XS-327 for thin build sealer, awesome overall protection, doesn't add thick coating material on to the concrete so is great for keeping the look of concrete.  Comes in Matte or Semi Gloss.  Good for beginners.  Apply by roller. 
  • Looking for something a little thicker, or that will darken the concrete more (wet look)?  Amperseal.  Available in Gloss, Satin, Flat.  Can be sprayed or rolled on.  While not 'hard' to apply, may take some practice to make perfect.

Concrete in general (stamped patio, pool surround, driveway, medium to low traffic interior flooring)

  • Superseal 2000.  Acrylic, solvent-based sealer.  Can be rolled, brushed, or sprayed on.  Re-application is simple, just clean, dry, and then re-apply sealer over the old sealer.  Some states regulate VOC levels of sealer (ie. California) and these states (check your local laws) need to order Gemkote 100 VOC.  Same sealer, just lower VOCs.

High Traffic Concrete Floors (Garages, showroom, industrial shop floor, commercial concrete flooring)

  • Epoxy and Urethane coatings.  Epoxy is good to add thickness, imbed colored quartz sand or acrylic flakes.  Urethane is harder, better for durability and can go direct to the concrete, or as a top layer over epoxy.  Concrete can be acid stained prior to coating for a designer look as well.