I would say that the 3800x will last longer. Here's a catch 22 though. If I've read right, AMD will be releasing their 4000 series of CPUs which should drop into your board with a bios update.
For example, I've got a 1st generation b350 board, but if I update my bios, I can use almost any of the 3000 series CPUs. So with whatever board you select, that may be an option.
I guess what I'm saying, there's nothing wrong at all with the 3800x if that the route you go. But you might consider the 3600 or 3600x for now, wait for the 4000 series to land, and if they are a significant improvement in performance, update your bios, grab the fastest CPU from that series you can and sell your 3600/3600x. Just an idea you may consider.
But if you want to set and forget the CPU, then buy the best cpu you can afford today, overclock if you like, and be happy.