Before making the decision on whether to build from source or not, it may be best to review a few of the advantages and disadvantages.

Disadvantages
1. Time
It takes time and effort to compile from source.   There are things you will need to learn and problems you will need to fix.  It is just more work to compile from source.
2. Transfer of Knowledge
If your organization does not have a plan to transfer the information on how the compilation was done and a transfer of the skills needed to compile and to maintain Postfix, then do not go down this road.  Company after company starts the process but finds themselves with applications that no one on staff can manage, with no documentation and no staff to solve the problems of updates.  When you compile a program transfer the knowledge through clear documentation and training of subordinates.

Advantages
1. Specific Build Options
When you build from source you can specify each of the options that go into the build process, eliminating options you do not need and adding those options that are most important.  This provides a much smaller and more secure product.
2. Version Freedom
You can download and install any version of Postfix you want to use, you are not tied to the version that is in the repository.