Ceramic Coating - Are they all the same?

To put it bluntly, no.  Every manufacturer puts in a specific % of the active ingredient in their bottles.  Cheaper bottles typically have less active ingredients, and most of the ones available for purchase on eBay or Amazon are what we call consumer grade.

Professional grade bottles are available only to individuals trained by the brand.  There are 2 companies that I'm aware of that offer this: cQuartz and Ceramic Pro.

I've seen videos, and it seems simple enough.  Why is the professional grade exclusive?

Because the professional grade has a higher content of active ingredient, it's basically thicker.  If not applied properly, it can leave some very unsightly residues on your paint surface.  This makes for a very ineffective product and leads to poor consumer reviews.  The manufacturer wants to make sure that the entire application process is performed correctly for the optimum performance.

What's the difference between consumer and professional grade?

Manufacturers recognize the DIY consumers.  In order to do this, they had to create a product with the least likelihood of error.  Like I said earlier, professional coatings are more expensive with more active ingredient, and although consumers may want ceramic coating, they may not necessarily want to pay the higher ticket.