This mainly on behalf of my wife who's looking at getting an iMac to replace her Windows laptop. How noticeable is the speed difference between standard hard drive and the SSD drive? I know bootup time is quicker but mostly we let our machines hibernate rather than turn them off so that's not really an issue. She'll probably run a VM as she's some work stuff that is Windows only but other than that she doesn't use her current machine for anything heavy duty like photo or video processing. From other threads it seems like the 512Gb SSD would be the one to go for but given that it's an extra £400 ($600) here in the UK the extra speed of the SSD would have to be significant to justify it.