I don't think sealed are a big deal unless you're putting them on a bike with interrupted housing. THEN they're important (assuming contamination is likely).
I've had problems with plastic ferrules. By a pretty huge margin, the housing itself will outlast plastic ferrules. Because they're soft, they introduce a vagueness to shifts as they squish and deform (esp as they age). Metal ones don't do this. As for which metal, I'm not sure I've developed a preference there. I think like cable ends, they're surprisingly expensive to buy in bulk. You can get them, but you're talking about shop quantities and fairly large expenses for a home mechanic. I think "home mechanic" ferrule quantities are typically a dozen or fewer consequently. I think I've usually bought them in quantities of half a dozen at most, and that's been awhile.
I've had problems with plastic ferrules. By a pretty huge margin, the housing itself will outlast plastic ferrules. Because they're soft, they introduce a vagueness to shifts as they squish and deform (esp as they age). Metal ones don't do this. As for which metal, I'm not sure I've developed a preference there. I think like cable ends, they're surprisingly expensive to buy in bulk. You can get them, but you're talking about shop quantities and fairly large expenses for a home mechanic. I think "home mechanic" ferrule quantities are typically a dozen or fewer consequently. I think I've usually bought them in quantities of half a dozen at most, and that's been awhile.
