This paper analyzes the characteristics of various mobile operating systems (OS) launched between 2015 and 2019, focusing on features like user interface, security, memory utilization, architecture, and processor performance. It highlights the rapid evolution and obsolescence of mobile technology, providing a comparative overview of systems including Android, iOS, KaiOS, Windows, and Sailfish OS. The findings indicate that while the mobile market offers diverse options, the fast-paced advancements create challenges for consumers in selecting the right device.