These is a line separating the bookmarks bar and the address bar in Orion, which makes the toolbar slightly taller than the Safari's toolbar.
Also an inconsistency in shading.
Fortrikka It does not look like the line accounts for most of the height. It seems that the toolbar height is inaccurate.
Safari's left window.
Fortrikka The extra line does account for the extra height. With the bookmarks bar hidden, Safari and Orion have the same height.
eirk Oh so by subtracting them logically it's the line, ok