I only use the disposable ones and the parchment triangles mostly for decorations using small amounts of icing in different colors. I used the vinyl ones a couple of times only, but couldn't get them clean enough.
I use one featherweight.....the big one with my icing tip to ice cakes........all the rest of the time I use the disposable!! I'm lazy and hate having EVEN MORE stuff to clean when I get done destroying my kitchen.........I mean......making a cake!
God's Word will either keep you from sin; or sin will keep you from God's Word.
Lately I'm using the plastic disposable bags a lot. If I need small amounts of one color, I use parchment with no coupler. I have the 16 inch featherweight with the icer tip, which I only use half the time anyway (like icing by hand better.)
I use a 24" heavy weight for icing cupcakes and cakes, lightweights for when I use the same color, but need to change tips. The disposables for general decorating, and the parchments for small amouts of icing.
Featherweights for buttercream, and disposables for royal - I wouldn't want to risk any greasy residue in the featherweight bags ruining my royal icing! For small amount (for FBCTs and the like), I use parchment without a tip - they can just be tossed when finished!
I use Wilton's disposible bags and re-use them about 2 or 3 times.... I once bought pastry bags from ebay... for savings.... but they just weren't stirdy enough they couldn't handle stiff constitency....
I buy a pony roll of parchment (12" x 700 feet) ~$40. It lasts forever. I don't cut into a triangle, I use a rectangle and it is really strong. Not to mention NO CLEANING!!! I hate disposable because they are slick. If I need a big bag I use a 16" Ateco canvas pastry bag. The featherweights blow out and make me really mad. (I guess I'm too strong for my own good! Sheera!)
It's not how good you are, but how well you can fix your mistakes.