Around here, in the regular grocery store, they are near the same price, with a BIG bag of whole carrots being cheaper, but plenty of people don't/can't do the big bag. Carrots don't really ever spoil, but whatever, not everyone wants a fridge full of root veggies.
At costco, the big bag of whole carrots is cheaper than the big bag of baby carrots, but sometimes the whole carrots are out for a month or two. In that case, the costco baby carrots are still a better deal than the regular grocery.
I like the big ones, because the baby ones taste slimy and too wet to me. The kids and H don't care. IMO even baby carrots are too big of chunks for soups/stews, but harder to slice, so I also dislike them for that reason.
In the summer we grow our own and get them at the farmers market. Much more flavor (sometimes admittedly its a bitter flavor, but still, they taste carrot-y).