I just went to Silver Dollar City for the first time over Christmas. Some people like it even more but I definitively think Dollywood is better. It just feels more set up to handle bigger crowds. The cave at SDC is amazing though.
What I like about these parks is that they really offer something for everyone. You could spend a day seeing the entertainment/doing rides. or just enjoying the food/atmosphere. Also there are really no duds in the ride collection. I think the Dollywood area is easily may favorite place to vacation in America outside of the parks around Orlando or LA. Everything is a much better value too and the national park is something that those other places can't replicate. We are talking about doing a big family vacation this summer and there really is not an affordable place within driving distance that offers the variety of Dollywood and the surrounding area.
On the coaster I thought I heard it was 50 million which is pretty significant or just how much major coasters are going to cost now with inflation. Maybe its because of the long track in this case. I imagine Disney spent at least as much for slinky dog for a worse coaster.