I have used Jenkins previously and I have found CircleCI is much better.

Previously, we were using manual deployment, which was error-prone and subject to a lot of steps. Some other products, such as VSTS build services were either too expensive or too difficult to configure, such as Azure’s Kudu deployment. Hence, we were looking at alternate solutions and found CircleCI which has worked well for us.

Since it was quite easy to set up the build/job in circleCI.