We have about 20 quail, in a large enclosure.
The can be quite "flighty" (suicidal!) though ours arent too bad - only fly out occassionally & are so surprised theyve been easy to pick up again... though one went off into the trees & was "retrieved" by one of the kittens!)
We feed ours layers pellets, though you can get specialised feed (not round here!)
I wouldnt keep them in with other poultry, just because of their size & relative possessive/aggressiveness of the males.
I find their whistling quite sweet... but it is seriously loud & can go on quite late into the evening!
We've found them really easy to keep ... major problem is their propensity to get "gummed up" toes & feet - some have lost their claws and even toes following infections once they get sticky balls round the feet, especially in winter.
they lay lovely eggs, almost every day but only between about April & September/October. real fair-weather ladies!
Feel free to ask more specific questions - thats all I can think of for now