josh wrote:

IMHO, they should outlaw the B channel. Water will follow that bend right
back into the fascia. Again, IMHO, B channel is made for those who want to
take a short cut at your expense. They don't like trimming edges of
existing shingles, so they cover them up, which creates problems which
aren't noticed until they're long gone.

Whatever roof edging you choose, the bottom edge should have a kicked
out lip. That makes the water drip free from the fascia instead of
running down it, prevents capillary action from pulling water up under
a flush piece of edging, and, most important, makes it easy to repaint.
The tip of the brush will run up behind that kicked out lip and there
won't be any exposed edge-of-paint-film. Makes cutting in a snap.

R