You'll get a LOT of different opinions on this one. I'm a hobby baker and give away my cakes so nobody is picky about which frosting I use; they love all of the buttercream versions.
Here's a link to a thread on Wilton.com with 2 superb crusting buttercream recipes which I use all the time. One of them is the Indydebi Crisco based buttercream. Indydebi posted her recipe in 2008 when Crisco still had trans-fats. When Crisco changed to zero trans-fats, I quit using it and only use high-ratio for my recipes.
Re: the taste~~Buttercream with real butter in it tastes better. I don't think anyone will disagree on that point. However, the majority of regular (non-cake-obsessed) people, probably can't tell the difference. You may want to make 3 batches, high-ratio only, high-ratio and butter 50/50, zero-trans-fat Crisco only and have friends/family do a taste test comparison.
Also, frosting made with high-ratio shortening will taste better, smoother, etc. than frosting made with zero-trans-fat Crisco. The high-ratio formulation allows the liquid and shortening to "blend" much better than zero-trans-fat Crisco.
If I know that a cake may not be refrigerated properly (which is most of the time.....), I use a suggestion from BlakesCakes for a room temperature, stable buttercream filling/frosting:
Equal amounts (50/50) of homemade high-ratio frosting (with no real butter), and canned cream cheese frosting.