I personally chose and built my own PC with the help of my husband who is an IT and his friends who have knowledge about PC.
There are two main reasons why customizing your own PC has more advantages than buying a pre-built system that already selected for you.
Performance and quality of the PC are determined by different parts used or make up a computer such as the processor, drives, memory, video cards etc. When you build your own PC, you have the freedom, without any restriction, to select different parts that best match what you need or you desire specially when you want it for playing the latest PC games on max settings. You allow full customization and ability to upgrade internal hardware to create a powerful PC/computer system.
In addition to that, you will gain knowledge and great insights in computer by learning and understanding the role and purpose of each parts/components of the computer system, how it works together and how they fit together into the motherboard. It is very essential for the user to have this knowledge when troubleshooting computer problems to avoid hiring technicians or expensive repair services.
However, remember to do this, you must have a support system or need a help from someone who is knowledgeable with computer parts and make research about computer parts because if you don't have knowledge it might be difficult for you and stressful and may face different risks.
Cheaper. You can have variety of choices and can choose a lower price but with the same specification options with other brand. You can also focus on the features you need or want and leave out those you don't need. Consumers can save through buying third party parts from small manufacturers/retailers. Mall price is more expensive compare to other sellers/market. You will just have to pay for the computer parts and you will not need to pay for the assembly cost and other charges to build the computer for you when you buy a pre-built computer system.