I've been working on browser performance for this website & have some observations:
The biggest performance killer is the display of airmets/sigmets/tfrs -- the problem has to do with the way Google Maps draws the lines. Turning these off allows you to scroll/drag the map more quickly.
But... I like displaying them, so that's not a viable option (to me)...
For Windows, IE displays the fastest -- Google Maps uses VML to draw the lines which makes it quick. Firefox uses SVG which is slower, but okay. The website works for both, but if performance is an issue I suggest going with IE.
For Mac, VML isn't available. Apple just released (yesterday) an "Safari 3 Public Beta", which is an immense improvement to the Safari browser. I _strongly_ suggest you use this new browser (
http://www.apple.com/safari). It's also available for Windows and works pretty well -- not as quick as IE for dragging airmets, etc., and about as quick as Firefox (on Windows).... Safari beta is faster than Firefox on Mac, previous Safari could be miserably slow on Mac.
Enjoy!