I don't know about Krylon "Fusion," but I still use Krylon Primer out of the can. (Part No. 1317 Ruddy Brown Primer) I find that it comes out the can very well, provides a nice, even coat and will dry very quickly. It is the only canned paint that I still apply to models. The paint is listed as safe for plastics - and I have yet to have it harm any plastic.
Even though it's listed as "Ruddy Brown," I find that it has a nice deep rust/red primer color to it. Using the "salt technique," it provides a nice base color after the dried salt is removed from your finish coat.
Hope this helped.