To go up one level press Command and click on the title bar. Pretty standard metaphor across the OS. Or alternatively if you are drilling back and forth through the folder hierarchy then switch to Column View.
And if you actually think that Ubuntu's woeful file manager is anyway comparable to OSX Finder then I really can't help you.
What exactly do you need your file manager to do? All I need is some handy buttons and icons to click in order to move around easily. Nautilus even has the ability to go directly to a specific directory by typing it out (with tab completion) and supports browsing remote file systems through a variety of protocols. I recognize my needs are different from the average user's (I actually mostly just use the terminal and xdg-open instead of a file manager). But what features in particular do you think Nautilus is missing?
And if you actually think that Ubuntu's woeful file manager is anyway comparable to OSX Finder then I really can't help you.