Well, I bit the bullet and ordered my 27" 5K iMac today. I chose the base model and upgraded the 1TB Fusion drive to the 512GB SSD. After reading so many posts about choosing SSD over the Fusion Drive, I decided to do as most people recommend. My Late 2013 iMac had the 1TB Fusion Drive and it wasn't bad honestly, but I guess the SSD portion was bigger back then too (128GB). Anyways, I'm stoked to get it and can't wait. Thanks for the suggestions and recommendations!