I just recently came across these apples.
Essentially, from what I understand it is a hybrid of the Red Delicious and the Gala.
So, yes, it is very sweet (like a Red Delicious) but not mushy like it's parent. But it's not exactly crisp and light like a Gala can sometimes be; rather it has a certain firmness to its flesh, best described (at least for me) as akin to Korean Apple Pear.
I think I"m going to add these to may pantheon of favorite apple varieties, right up there with the Fuji and the Honeycrisp.
Do you like Sonyas?