That fat is actually why rib-eye is so well regarded and more expensive than sirloin. It's called marbling, the fat that runs in the meat enhance the flavor and makes it more juicy and tender than sirloin. I could understand how people may not like it as I have met a few who legitimately dislike the taste of fat.
Sirloin on the other hand is considered one of the lower quality cuts of meat because it is almost entirely muscle and thus typically pretty tough, especially cooked well done. I consider well done sirloin practically inedible myself.
My personal favorite cut of meat is rib eye, not because it's the best cut of meat but because it is a great cut of meat but still in the range of what I consider to be acceptable affordability for a food item.