I must admit that Josko's point is well taken. I like to fish big poppers and don't exactly have the best time casting them on the fly.
I do tend to try them after I have already taken a few fish below surface. Slack tide and low light, especially in the evening after things have calmed down from the day have always been good for me on poppers. However, my all-time popper favorite is big nasty windy conditions, fishing in between the swells over structure or in the wash where waves crash onto rocks--kind of tough on the fly but results in big bass.