I'm experiencing a delay of almost one second when accessing on menus,  
i.e. there is a long lag between clicking on a menu title and the menu  
actually showing up.  That shouldn't be.

Also, some mouse-hover effect seems excessively slow:

M-x lisp-interaction mode
(frame-parameters nil)
C-j
(go to the "..." ellipsis)
RET
move mouse over the buffer contents, which are then shown with a green  
background.

The green background appears very gradually, it takes about 0.5  
seconds to completely appear.

This is no the case in (Carbon) Emacs 22.

Other (re)drawing operations are very fast - scrolling etc. seems much  
improved from 22/Carbon.

NB, Emacs -> About Emacs should go to `about-emacs'. Remove "Report  
Emacs.app bug", I guess these go to the usual destination now.