I like Ubuntu the most. Cause it is maximally optimized for the server, easy to manage, and intuitive to understand everything. It is not Kali Linux, and Ubuntu has a proper terminal. It is more convenient to work with than Kali. But Kali Linux is also very seldom used. I bought my Ubuntu VPS https://www.hostzealot.com/vps/os-ubuntu from hostzealot. I like they always answer any questions and help me set it up if needed.