Pros
Decent to good pay when they are in demand for drivers. They will slide you a light, easy route every so often when things are slow. On those rare days you're making easy money.
Cons
Amazon Flex is great in a pinch, especially when you they increase the route pay, which happens fairly often. The work is the worst in the gig world, with typically 40+ deliveries to make and returns must be taken back to the station, no matter how far you are away. Compare this to DoorDash where you NEVER have to take anything back and when you're done with the assignment, you're done. Also, Amazon is ruthless, sending you up to 60 miles away to do your route, and no matter how far you are cast out, there is no extra pay for the extra distance. The people at the stations are weary grumps, but so are fast food workers when you're doing UberEats so that's not too bad...