I'm looking at getting a new 27" iMac (MK472LL) & while configuring it on Apple's site, I see that going from the default 1TB fusion drive to the 1TB SSD is an extra $900. That increases the price of the machine from $2,000 to $2,900. Basically a third of the price is on the hard drive alone. Compare that to going to a 512 GB drive for a $400 upcharge. File & document storage is not an issue. I have a Drobo with about 6 TB of storage space that I will be connecting to the machine, but that Drobo is a pseudo RAID device with spinners in it, so that defeats the purpose of having an on board SSD if I am running anything off that drive. Hence the reason I want to go with the bigger 1TB drive so I can use the Drobo as a true storage device & not a supplemental active drive. My question really is this. Is the 1TB drive worth the cost or will I be fine sticking with the $400 512 GB SSD? Keep in mind that I have zero desire or intention of ever opening this machine up to upgrade the drive at a later date which is why I want to try & future proof it as much as possible at the point of purchase.