What Big D said. The trick is to remember that the "Sol" in Micro Sol stands for "Solvent." If you can remember that it's easy to remember which does what.
I have both, but have rarely used them. I haven't had the need to do decals in a while, but when I did I used the gloss method. Paint a little brush on gloss coat onto the area where the decal needs to go, then apply normally. After you're done do a normal dull coat as part of the finishing process and it looks great. No sign of the edge of the decal if you do it right. Of course, this is for fairly regular surfaces, if you are going to try it on an irregular surface, then the Micro Sol becomes necessary.