Both are built around a battery. The pick depends on whether you want a simple flat export rate or to chase the half-hourly wholesale market.
Intelligent Octopus Flux pays a flat 23p/kWh on every unit exported, whatever time of day. Agile Outgoing tracks half-hourly wholesale prices and averages 9.09p/kWh — with individual half-hours spiking well above that on cold, high-demand evenings. Flux's flat rate beats Agile's average for most households; Agile only pulls ahead for technically engaged households who can actively steer exports into the rare high-price windows.