Well, in the end, it didn't look horrible... it just took Behr 7 painful coats, on long and winding trim, to get full coverage. After 4 coats you could still see through to the freakin' primer.
The other room, same trim, the SW paint did it in two.
Had similar problems when painting the bathroom when we moved in.... stupid

at HD sold us deep red Behr paint using the base for lighter coloured paint. Five coats on (and two days later), and I could still see through the damned paint.
Went back to HD and yelled at the person behind the counter about it being crap paint and he looked at it and said "no wonder, what dumb-ass sold you that? that's for
light colours". Uh, the other dork in your department... Gave us a new can of the same tint but using the base for deep colours. One coat covered everything up. Used the same deep base can in another room and only needed two coats to get it a nice and rich colour.
So... if you're putting on any sort of deep/dark/rich colour, be sure that they tint it using the right base can.