I bought a bowl with a 20-oz drink for $5 (sadly, no chocolate chip cookie was included at my local KFC); the bowl was also offered by itself at $3.99.
What's different with the Loaded Potato Bowl compared to the Famous Bowl is the addition of the bacon cheese sauce and green onions. It looks to be inspired by loaded potato skins, which tend to be topped with bacon, cheese, green onions, and sour cream.
I somehow found this to be less salty than previous iterations of KFC's Bowl. I think it's due, in part, to the bacon cheese sauce and the replacement of Popcorn Chicken with diced Extra Crispy chicken strips. The diced strips in particular feel meatier and have less salty breading. They're also crispier. Also, the bowl seemed to be slightly wider with more heft to it than when I tried it last. I suspect there is more mashed potatoes to go against the saltier ingredients than before.
Overall, I enjoyed KFC's Loaded Potato Bowl a fair bit. It's a kitchen sink approach to the signature KFC ingredients and the mild bacon cheese sauce does a fine job of pulling it together without being overwhelmed or overwhelming.