I think your Wilton recipe would be greatly improved simply by using unsalted (sweet) butter instead of shortening, and using a high quality vanilla. If it is cloyingly sweet, you might add a pinch of salt. The many other buttercreams are more difficult to make, it depends upon what you are used to and what it is for. My last boss disliked me for calling the stuff in the can "**** -in-a-can", or in a take on a brand name "bettercrap". I hope I'm not offending anyone...... I'm very opinionated on this subject . Nothing beats a good scratch icing. Any good cook book will give you several variations. Try & taste! For wedding cakes I used an meringue buttercream, but have noted that the terms Italian meringue, Swiss meringue, or French meringue seems to vary according to their source (one book calls a method Italian, another called it French, etc.. I could be more specific but it's really just a matter of semantics. Any cooked sugar method will be more stable stand up better ). Shortening has a higher melting point than butter, therefore the butter melts in your mouth, whereas shortening may leave a film. Shortening stands up better in hot weather, due to its higher melting point, but you sacrifice taste - a combination of both might be desirable if weather is a consideration.

I hope I have not bored you too much. It feels like I running on, but this is one podium I like to jump on!