BB, hi and welcome to the forum. Now this is my personal opinion. I have made my own plastique and ordered it already made. I have seen posts on this website from people who claim to make their own and it works fine for them. I have never been satisfied with what I made, even though I know how to do it. I am partial to Barry Decor, but Albert Uster also has a very usable product. In lieu of the plastique you could also use Massa Ticino, very similar in texture and usability but with a neutral flavor. The Barry Decor is flavored with Oil of Bitter Almond so it has a Marzipan like quality to it. The Albert Uster brand is mild in flavor, and of course what you make yourself will have the most flavor, especially if you are making dark plastique.
As for a recipe can dig mine up if you need it.