Left to right these cans are VP Racing (not CARB-compliant), Just-Rite (CARB-compliant), Eagle (unclear if it complies) and No-Spill (CARB-compliant).
The metal cans on the left (Eagle and Just-Rite) make use of removable plastic funnels, the No-Spill has a stubby plastic spout, and the VP Racing has what looks to be a homemade spout.
The traditional vent allows this non-compliant can (VP Racing) to be emptied quickly. If it falls over while open it will spill and you have to be careful not to tip it so far that gas comes out the vent. This type of can was designed for the racetrack and is popular with landscaping crews
The Eagle Safety Can has a metal carry handle and a plastic pull handle that opens a spring loaded cap. When the can is tipped with the cap open gas pours into the funnel and flows to the machine you are fueling.
The Eagle can comes with a removable plastic spout that funnels gas into the tank being filled. It fits very well so there are no drips or leaks.
Just-Rite's safety can resembles Eagle's but the spout (funnel) is so small fuel will spill if you don't pour slowly.