Booster is smoother and bulkier than dip. It is therefore mainly used for baits, i.e. boilies, pellets, Method, Zig or PVA mixes, particles, etc. It is also intended to achieve the same flavor of the bait boilie as the boilie you are fishing with.
Dip is mainly intended for accentuating lures. It is extra strong and contains ingredients that are released from the lure at different speeds, directions and intensities. They attract the fish to the bait from a wide area and from different layers of the water column.