The other VPS managing modality is unmanaged or also known as self-managed. Here, everything is handled by the client, even the technical things behind the server management. The server provider does not perform any maintenance or installation of software. The provider guarantees that the physical server is in optimal conditions, but nothing else.
This modality is preferred by customers with knowledge and experience to manage a server on their own. This modality offers much more freedom to configure and manage the VPS server than a fully-managed plan. For instance, you decide what software to install without any delay or waiting time.
Since no external technical experts work for you, the price of the VPS rent is significantly lower. Moreover, the security of the VPS is in your hands. So, it can be as strict or relaxed as you want. Also, you decide the different access levels you want to grant to the different users.
Even though this modality offers the most freedom, its use should be considered by customers with advanced technical skills. It would be disastrous to be unable to manage the Moscow VPS once your website is online. You must be able to analyze the different traffic patterns to modify the performance of your server accordingly.
Hence, if you hesitate about your technical skills, do not take this option. You can always hire professional technical staff though. But in such a case, you should evaluate what is more convenient for you, a fully-managed plan or hiring in-house experts.