There are several disadvantages associated with vps hosting. Where there are many users running VPS there may be limitations in respect to processing time, RAM (Random Access ,Memory) especially during peak period due to overstretching of the shared resources.
Using VPS is challenging for those with limited experience. One is responsible for all configurations, management and administration of the server. Therefore you may experience some difficulties if you are a first time user, or if you are not tech-savvy. As a result, you may end up outsourcing to an expert to conduct server administration and management for you and therefore incur extra expenses.
There may be difficulties in some shared platforms where users share software components. As a result you lose the aspect of control as you will be unable to configure personalized settings independent from other users. Notably, the above drawbacks do not adversely affect usage of VPS but can be viewed as the challenges by users.