I currently own King quail, but if you are wanting eggs, I would go with Japanese quail. I used to own 8 girls, and they all payed twice every two days, but on different days (if that makes sense
so I got around 8 eggs every day.
I know some Japanese quails would escape your yard if you let them out, but I have a very secure yard, and I clipped their wings, so I let them roam during the day, and at night I brought them inside, into a c + c Guinea pig hutch. I did the same if it looked like it might storm.
They didn't ruin my garden, they ate of out my hands, and I had two that would literally hop into our laps when we sat on the grass.
Unfortunately, there was a massive storm when I wasn't home to bring them inside, and 5 of them sadly didn't make it
The other three were traumatised and one sadly died the next day.
The eggs were quite tasty, but only about half the size of a chicken egg. If you are thinking about 6 chooks, then you better double the amount of quail at the least.
That's the disadvantage of quails.
My neighbours have four chickens that lay them a nice big egg a day, and they all have gorgeous personalities.
Cons of Quails:
-most are escape artists
-don't lay as often
-will require more secure housing
-some may be frightened easily
Cons of Chickens:
-some can be loud
-likely to ruin garden
-do big poos
-will make more of a mess
-eat just about anything (I was mortified when my neighbours chooks devoured a poor baby water dragon while it was still alive
-if a chicken becomes broody, it will stop laying and will need to be sectioned off from the nest boxes as it will starve or die of thirst
On the upper hand, chickens can be trained to do tricks
Anyway, that is just my experience, I really hope it helps!