Pros
They pay you good money to work outside all day and exercise (running up to houses to deliver). It's a great feeling to know you're not stuck inside working in some stressful cubicle on a beautiful day. You can pick up or give up jobs whenever you want so long as your dropping a shift comes within 45min of your start time. The people are awesome You're an independent contractor, so no boss! It's just way too much fun. Not stressful at all. They give you a route w a set time of 4 hours. I usually finish delivering in half the time and still get the payment for the 4 hours.
Cons
Battling for blocks. You can't be overly dependent on flex for money especially if it's off peak. You'll start to freak out because competition is heavy to grab shifts. But typically I work 4 hours every day of the week, so it's not that bad. It drives up the mileage on your car. More recently they updated the app so you can't pick up more shifts until your scheduled block is over. Before, if you finished a couple hours ahead of your delineated finish time you would be able to start within the next hour. But now, your earnings don't update until the full 4 hours of your block is up.