That is great ! Our tools are also there for non code usage to offer a nice user experience around Pandoc using markdown as input.
Not there is not a one one comparison between the two. I think all the special features of bookdown are already in Quarto, and more new feature. However, book format is different - you won't have exact gitbook(), nor bs4_book() but Quarto book is based on Bootstrap 5 by default, so offers an other format.
Best thing to do is looking at Gallery (Quarto – Gallery) and the guide (Quarto – Guide) for authoring features and also how book project works.
If you are happy with how bookdown works and how its format looks, then there is really no need to make a switch.