They are excellent for meat and eggs. My only issue is that the eggs are relatively small when compared to chicken eggs so it takes longer to crack or peel the shells.
They mature in about 8 weeks meaning they can lay eggs and start breeding around that time. The meat from quail is extremely extremely excellent!!!! I'm a foodie and the quail meat from my own birds is a top tier meat. I have a thread called the Shinto Dragon Jumbo Coturnix Project that has some info on a fun project I'm working on.
I have a T5 light on my bird cages which stimulates my quail to lay approximately one egg per hen every day even through winter. My daughters love watching the quails hatch from the eggs and collecting eggs from the cages.