I have been very happy with my Ryzen build from last year where I was using the 1800x. I really did not need to upgrade, other than to take advantage of some of the improvements that AMD made in the Zen architecture. There is a slight speed difference between the two chips, which also is nice, though, I would have like to see a bigger bump in speed. The new 2700x includes a fan, but I am using water cooling, so no big deal for me.
In 10 minutes I had opened the case, pulled out the old CPU, installed the new CPU, cleaned my water cooling block of thermal paste, applied new thermal paste, and tightened the block to the CPU. I had previously updated my firmware to accept the 2nd generation Ryzen chips, so all I had to do is power on.
The Asus B350 ROG Strix motherboard recognized the new chip. All I had to do is reboot one more time. I did not change any settings. Booted into Ubuntu Linux without issue. Ubuntu recognized the CPU without issue. I did run some stress tests against the CPU, using the stress command and all appeared normal. No problems with the CPU handling the load and thermal temperatures were normal.
I do not use my system for gaming, but as a server for lots of Application Servers and a development machine. My workloads finished about 10-13% faster that the 1800x CPU, which is a nice performance. I could bump that up by buying a newer motherboard and faster RAM, but for right now I am very happy with the performance gains.