I love them. I have used the green for spirit hosts, which is great, and for rust effect on armor.
For ethereals, Ill offer this tip: if you undercoat them in white, they will be very bright. I basecoated white, then drybrush bone, then glaze(two coats if necessary), then dry brush bone, then drybrush white. Seems like many steps, but after my first SH, I wad a tad bit dissappointentes in the brightness.