The only thing I used Krylon for was when I had to cover a huge area (the hull of the C-57D saucer ship from Polar Lights.) I used 2 large cans of primer and 4 or 5 large cans of aluminum finish coat. It would have taken weeks and hundreds of dollars to use little bottles of model paint, and the high-flow rate of the Krylon spray was acutally an advantage in this situation.
Cons: Even though I had the windows open and fans in the windows, the entire basement and everything in it was covered with paint dust at the end of this project.
A lot of fine sanding was required between each coat, because it results in a "pebbly" surface out of the can. I had to apply many finish coats and use a lot of paint before it looked right for a spaceship model.
So, I cannot recommend it in general for the type of small models we usually build. I think it is fine for repainting your lawn furniture, and stuff like that!