Where you allways satisfied? No bad experiences with composers killing your film?
When I started out, say the first 20 years, stock music didn't even exist so it was either no music or original music.
I had only one really disappointing composer, a top-notch classical guitar player and I had barely enough money to pay for one instrument so I thought this guy would be perfect since I like the classical guitar very much. I liked his playing a lot, both on his sampler and his acoustic guitar. I asked him which one he prefers to play on, and he laughed and said, Always on the real guitar; it's both easier and sounds better. So then I asked which will he use for my film and he said, The sampler of course -- you are not paying me enough for the acoustic guitar, so I left and never came back to him.
I like to stay loyal to one composer as long as possible because then I can pay him less than he deserves when I have a low budget and have to pay myself less than I deserve, and later I can make up for both of us when a well paying job comes around. I select my composers first for the way they can take directions from me and only second how easily ideas come to them. The quality of their sampler software and how they use it has become a more important consideration lately as well.
Using one piece by someone like Dvorak in an eighty minute film is OK by my standards if there is a strong case for reverting to something very familiar. In those cases I still have to have the money to re-record the orchestra because the playing is usually still copyright protected.