I have no preference either way, I think there are benefits to each name.
I’d say a [name_m]Daniel[/name_m] [name_m]Hill[/name_m] is likely to have it all together. Because [name_m]Hill[/name_m] takes up less space and is comprised of so many vertical lines, it seems more formal and reserved. I like that but it’s sort of an “under the radar” kind of name.
Now, [name_m]Daniel[/name_m] [name_u]Gray[/name_u] is a bit more “round” and takes up more space. Because of that I’d say a [name_m]Daniel[/name_m] [name_u]Gray[/name_u] might be more outgoing and a bit carefree. It does stand out more and seem more balanced when written which may be important depending on your career.