Both have their pros and cons. Pepper spray can generally be made smaller, and can therefore be easier to carry on a keychain or in your pocket. Gel typically requires a larger can, and is easy to clip to a sun visor, a book bag or keep on your nightstand. Gel is less affected by strong winds and provides a more concentrated stream, but spray covers a wider area and requires less precision. Also, pepper gel is better for inside a closed area, because gel is much less likely to be drawn into HVAC systems.