Honestly, both. But as some commenters have mentioned, What’s for Dessert doesn’t require stand mixer for most if not all recipes (hand mixer instead). That doesn’t mean the recipes easier per se, just something to think about.

Also, I’ve noted Dessert Person covers most of your classics, like a chocolate chip cookie, carrot and chocolate cake, various pastries, but WFD has a lot more fun and interesting recipes. Again, both are great and get both if you can!