I'd also add that flowforms typically have venting holes on the bottom surface (sometime the top too?)
Flowforms also tend to have simpler bridles. The bridle is single row of attachements.
Parafoils tend to have 2 or 3 rows of bridle attachments.
Flowforms are supposed to be more stable.
Flowforms are what the KAP folks often use.
Peter Lynn designed a parafoil that a lot folks use to help keep the really large kites in the air and stable.
Peter Lynn style parafoil:
There are plans on the web for building both kinds. I've built a couple parafoils, I haven't made a flowform (yet)--edit: oops yes I have, I forgot.