Why we love our iMac 5K?
It is a very powerful machine and we use to edit RAW DNG footage from our Blackmagic Cinema Camera.  We edit footage in Adobe Preimere and color the footage in DaVinci Resolve.  We love this machine as it has a beautiful 5K resolution with Retina display plus it is a powerful and fast editing machine. 
•  4.0GHz quad-core Intel Core i7, Turbo Boost up to 4.2GHz
•  16GB 1867MHz DDR3 SDRAM - two 8GB
•  2TB Fusion Drive
•  AMD Radeon R9 M395X with 4GB video memory