It was straightforward to order my coating - it is a warehouse floor coating, and it landed at my door a few days after I placed the order. I simply went to the rental house, got a set of diamond bits, and rented a gas floor grinder. Cut the floor down with that, already had a respirator, and applied the coating over one very long day. It is a 3-coat urethane system (primer, color coat, clear coat) with an anti-skid additive and a flake. that had all kinds of "ratings" and is perfect after several years. It is overkill for a house garage, but I often drag some heavy steel items around and didn't want a floor that would get all scuffed/torn up.
A friend did his floor at the same time (figure we could both used the bits, etc.), and it is also perfect. It may not be the "Stonehard clad" you are specifically speaking of, but there are other commercial coatings that are also excellent products. Stonehard is simply a brand-name epoxy and urethane floor protection system. I also noticed some Stonehard listed on eBay currently if you really want to buy it and not have a "pro" install it.
If I recall correctly, I had about $1000 in doing my garage floor; the "pros" wanted $6,000. I agree they have some tips and tricks that are helpful, but for 5K I figured I could do my own research and figure it out. Honestly, it is some work, not really a fun job by any stretch, but also not exactly rocket science, just mainly a little research and labor.
Both Epoxy and Urethane coating can be great for a garage type of floor - neither is bad, and neither is perfect. Both are a slight compromise, but if you stick with the industrial/commercial coatings, you will do fine. The stuff at the big box stores is really what you need to avoid; it is made for a price point and a quick install. Also, without the proper prep, it doesn't matter what you put down; it won't last.
Floor coating rating info if you are interested.
(Abrasion Resistance Method: ASTM D4060, CS 17 wheel, 1000 cycles, 1 KG Load Result: 18 mg Loss Adhesion: Cross Cut Method: ASTM 3359 Result: Passes 5 Adhesion: Elcometer 106 Method: D4541 Result: Exceeds 500 PSI Dry Heat Resistance Method: ASTM D2485 Result: 400ºF Flexibility: Conical Bend Mandrel, 180º Bend Method: ASTM D522 Result: Passes 1/4” Impact Resistance Method: ASTM D2794 Result: Direct – 160 in. lb. Pencil Hardness Method: ASTM D3363 Result: 4H Salt Fog Resistance Method: ASTM B117 Result: Passes 1200 hrs Accelerated Weathering Method: ASTM D-4587, QUV Result: Passed: 1500 hours, Abrasion results are greatly improved with the addition of our anti-skid. Abrasion Resistance Method: ASTM D4060, CS 17 wheel, 1000 cycles, 1 kg load Result: 23 mg Loss Bond Strength Method: ACI 403 Result: 325 PSI (Concrete Fails) Dry Heat Resistance Method: ASTM D2485 Result: 350ºF Flexibility: Conical Bend Mandrel Method: ASTM D 522, 180º Bend Result: Passes 1/8” Impact Resistance Method: ASTM D 2794 Result: Direct – 160 in. lb. Result: Reverse – 160 in. lb. Pencil Hardness Method: ASTM D3363 Result: H Sward Hardness Method: D2134 Result: 44aa)