As an aside, I used the Rustoleum kit on my shop floor, it's been in service close to 9 years and has endured typical home shop use with good results. Lots of folks will poo poo these modestly priced products, but if applied properly, in my experience anyway, they are a great deal.
With any garage floor coating, the real deal is to make sure the floor is very clean, no oil or dirt. Like any coating product, preperation is very important for a good finished product.