Magic Mouse is not your typical mouse. In my opinion it is the best of both world combined. My most used feature like most people is scrolling a page, do you know how beautiful it is to just swipe the top of the magic mouse and have it scroll...... PRICELESS
The only downfall is the batteries they go through them quick. A good suggestion is to buy rechargeable ones. Now my opinion of the Magic Trackpad is, that it's an excellent option as well, but when doing work in photoshop and other precision techniques it is more difficult to accomplish compared to the mac.
Now with practice you can master anything and these are only my experience.