Difference between Systemctl and service command

With borrowing from this answer:

service is an "high-level" command used for start, restart, stop and status services in different Unixes and Linuxes. Depending on the "lower-level" service manager, service redirects on different binaries.

For example, on CentOS 7 it redirects to systemctl, while on CentOS 6 it directly called the relative /etc/init.d script. On the other hand, in older Ubuntu releases it redirects to upstart.

service is adequate for basic service management, while directly calling systemctl give greater control options.

Moreover, systemctl runs services file from this path: /lib/systemd/

service operates on the files in /etc/init.d and was used in conjunction with the old init system. systemctl operates on the files in /lib/systemd. If there is a file for your service in /lib/systemd it will use that first and if not it will fall back to the file in /etc/init.d. Also If you are using OS like ubuntu-14.04 only service command will be available.

So if systemctl is available ,it will be better to use it