If I had an unlimited budget for computer equipment, I would have bought the 27" 5K IMac fully loaded...
I'm typing this on my new 27" iMac (4.2 GHz, 16 GB RAM, 512 GB SSD). The model is 'mid 2017'. It's replacing an 'early 2008' MacPro that has served me well. The cost is painful, but heck, I've been buying Apple computers since the very beginning - 1978 - and I'm not going to stop now. Call me obstinate.
I'm not worried about the USB-C interface - there will be adapters available when necessary.