Pull cons:
1,May has a little delay, depends on pull rotate time
2,Client is thick
3,Need coordinate to load balancer
4,If no data in queue, client may pull many useless request

Pull pros:
1,Pull is better in dealing with diversified consumers
2,Consumer can more effectively control the rate of consumption.
3,Easier batch implementation

Push cons:
1,Once a transaction is sent - it’s gone. No “recorded history”
2,Can’t transform “massive sets of data” at once
3,Need db to storage status

Push pros:
1,Fast notice and instant transaction communication
2,Transaction by transaction / guaranteed delivery mechanisms
3,Client is thin

Push vs Pull:

Pull is good at massive traffic request message system.
Push is good at instant communication and not too much traffic