After morning shift I don't have problem at all. Though the first night day can be too long.
After afternoon shift I can't fall asleep until 3-4 am for the 5th, 6th and off days. The problem is that morning shift follows it, usually I go for the first morning day after 1-2 hours of sleep, it's so great, you can imagine.
After night shift I'm awake too early, usually around 3-4 am, best case 6 am.
Same, first afternoon day is pretty long.
Apart from that I don't have sleeping problems.