PG and VG are both base liquids in your e-liquid, and are both odorless. PG is tasteless and VG has a subtle sweetness. PG is less viscous than VG and acts as a better carrier for the flavouring and nicotine, providing more flavour and a more noticeable Nicotine throat hit. A higher VG content e-liquid will provide denser vapor production and be a bit sweeter, but the overall flavour and Nicotine throat hit well lessen. A 50/50 blend is suitable for most devices. High VG blend juices should only be used in drippers and tanks recommending a high VG blend. High VG blends can shorten the overall lifespan of a coil.