Taste and texture of particular species can be a matter of personal preference, time of the year, climat, feeding, and it is highly subjective, debatable and often controversial.
So I am on my way to try every possible game bird I can. I raised and consumed ringneck pheasants, they are pain to hatch, and raise (large pens needed). I was not impressed with their meat, it was good but personally Guineas taste better to me and they are much easier and cheaper to raise if you have a pasture.
I raised few Chukars this year, they were delicious, but so are my jumbo coturnix, now I am out to try some Butlers for comparison. If Butlers won't turn out superior to the others I mentioned tastewise I will stay with Chuckars and Coturnix since Chukar is relatively large bird and reaches butchering weight in 4 months (faster then bobwhites).
Generally coturnix can not be beaten cause of their prolific nature, shortest incubation period, easiness of hatching and raising, record short time from egg to table.
Basically they blow away all other species with those adventages.
If I was to raise one kind only that would be coturnix hands down.