Well, if your really want to figure this one out, consider that on their moral scale, killings not a bad thing. There are people out there who really don’t see what the big deal with taking another human being’s life is, so, to ask them if jules and Vincent are evil, they’d say no without hesitation.
Now, ask the same question to any god fearin’ man or woman, and their answer, if they truely believe in the teachings of the bible, would be yes, again without any hesitation.
A third category, the folks who have a good moral compass, but can very easily see how some people don’t/can’t, they’ve got to think long and hard to honestly answer that question.
So, in my opinion, they weren’t evil men at all. Because, to me, when you get mixed up in that kind of shit, you have got to fucking know that without a doubt, you’re laying your life on the line. The people they killed knew what they were getting into, in the first place. If you can’t stand the heat, stay out of the fire.