Ok what I have read so far is that with a SSD you can boot up the Mac much faster and the apps also start faster than using a HDD. But what exactly is this good for if most users (if not all) never turn their iMac off and thus don't have to boot it. And if you just wake it up you don't even have to reopen your apps. Most users use the same apps everyday and just can leave them all open using Spaces. The only real advantage that would come to my mind is that it is completely silent. A big disadvantage for me is beside the price that you should not write/delete too much on it as this would speedup the degradation process of the SSD.