I did not test many games as I don't see the logic in dumping my own games when I already own all of the ones I wanted and I'm not into doing anything as risky as sharing, but I noticed that different versions of Vitamin have different success rates.
Especially the leak uses a different launch method and even though I didn't install it to test if it's working, some games like EUR Hungry Giraffe worked with the leak but not with the proper release.
It's a real pain that one cannot have both installed at the same time as this would make things easier to compare, but I guess it's better than noting for people that really don't want to spend the money on games.