A great advantage of VPS, compared to both shared and dedicated solutions is snapshot technology support. A snapshot is a state of a system at a certain point in time. It works like game saves in your favorite computer game. If a game is not going well, you can exit and start from a checkpoint. A snapshot works the same way; if you need to go back in time, your system can be restored from a snapshot to its previous state. It is extremely useful in case of a system failure or simply if you run complex tests and wish to save your progress. Unlike a backup option that copies the whole system each time you run it, a snapshot contains only changes. This means that a snapshot takes less space than a backup and can be created/restored quicker. It does not mean that you do not need backups though. Backups are still life-savers in case of operating system failure. Don’t forget to store them externally.
Dedicated server hardware is also limited to a single tenant usage whereas VPS hardware is shared by multiple hosting customers on one partitioned web server. The latest trends in web hosting have seen companies move beyond the single server model on cloud, VPS, & shared platforms to host multiple copies of a website's files and use network load balancing software to route traffic to the hardware with the most open processing capacity for better response times.
You’re paying more, so there SHOULD be a minimum uptime guarantee and better server speed. Look for a host that offers 99.5% at a very minimum, although ideally, I’d rather go with someone who offers 99.9%. Search through some reviews as there are many who have put this to the test. For example, any of WHSR’s many web host reviews include an uptime record as one of our key tests.

I can’t say it as a disadvantage of VPS hosting because many of our VPS hosting customers have server administrator to manage their VPS and they manage it in very efficiently manner. But this doesn’t everyone must have server administrator, we have content-rich knowledge base on VPS hosting for our self-managed customers.Also, a managed service option at very affordable price.