Scrum is Good but there must be some drawbacks / disadvantages in Scrum. What are they ?

As far as i know Its hard to get into Scrum and its implementation in the organization is also hard. Because some people in the team or management would not be ready or willing to accept it.

Any other things ???

In Scrum, there are three primary roles:

1. Product Owner
2. Scrum Team
3. Scrum Master

The Product Owner is mainly responsible for gaining maximum business value, by gathering all the inputs from the customer and what should be produced to end user of the product. These inputs could be from Team Members and stakeholders. After gathering all inputs from customer / team members or stakeholders Product Owner translates them into a prioritized list.

In some cases, the Product Owner and the customer are the same person; in
other cases, the customer might actually be millions of different people with a variety of needs.

The Product Owner role could map to the Product Manager or Product Marketing Manager position in many organizations.

The Scrum Team develop the product / project that the customer is going to use: (Software or website / web application)

For example. The team in Scrum should be “cross-functional”.
A team in Scrum is typically five to ten people, although teams as large as 15 and as small as 3 report benefits, and for a software project the team might include analysts, core developers,UI designers, and testers.

The ScrumMaster is one of the most important elements of Scrum success. The
ScrumMaster does whatever is in their power to help the team be successful.

for More info : read my previous article.
scrum-master-n-responsible