Raw edge applique is my favorite. I use heat and bond lite because it works, it's less expensive than steam a seam 2 lite, it stays good for years, it holds in place for years without stitching it down and its available in a roll.
Steam a seam 2 lite is a very nice product, but I think heat and bond lite is easier to use.
Wonderunder may have changed in recent years, but the older it is the less it works, until it doesn't work at all. You used to need to use it within a year or it loses its properties.