Actually -- you can convert your stuff over pretty easily ... the .jempegrc format is the following:

jempeg.soup.count=3
# a search example
jempeg.soup.0.name=Name of First Soup
jempeg.soup.0.externalForm=search:(title contains test)

# a tag example (By Artist)
jempeg.soup.1.name=Name of Second Souip
jempeg.soup.1.externalForm=tag:artist

# All marked tunes, then By Artist
jempeg.soup.2.name=Name of Third Soup
jempeg.soup.2.externalForm=search:(marked)~tag:artist

Basically the externalForms are ~ separated... You should be able to convert over relatively easily if you have a lot of them and you don't want to use the UI.

Mike