We've had lovely experiences at both. BC seemed a bit more magical but I really think that was only because we'd received a nice upgrade we weren't expecting. If this helps, and it's *only our experience,* but trending with the common thought that BC is a bit more family oriented, we found that CMs were more likely to engage with us there. At YC they were outstanding, but polite nods, "Good Mornings," etc were about the limit. For the most part, YC CMs let us be. Again, this was only our experience, and yours may vary, but you're asking for opinions. Food options were similar, and both resorts are tied for our favorite, so in our minds, you can't go wrong!
In summation, if you're looking for a more grown-up, slightly more upscale experience, I'd go YC. If you're looking for a bit more family-friendly, go BC. I can say without question, the BC lounge was always more rowdy and had a much higher ratio of children about.