ok because i design and build websites on a daily basis, i'm gonna give you my nerd opinion lol.
PROS: aesthetically, its gorgeous, simple and very clean. the design makes the line seem even more high end than it is. easier to navigate, and the viewing is much better. so all in all, the layout is way better because it allows you to see so much more than before. AJAX shopping carts are always better for those who hate having to load anew page everytime they add something to their cart. so thats very helpful. Having all of the colors out (even if they're not 100% accurate) is easy to skim thru so you dont have all these annoying pop up windows. The video tuts are great.
CONS: because its in flash, searching anything MAC related in google will only take you to the old layout. The problem with that is that the old layout doesn't exist. Flash isn't spidered in search engines, which makes it very hard to search for MAC SO SCARLET LIPSTICK (for example) and be brought to the MAC website. They should know this by now, it's 2009. c'mon! It does load a lot slower, but once it does load, your cookies/cache will be able to bring it up very quickly - at least for me. also because its in flash, people with slower machines will probably say "fuck this" and leave lol.