UE4 has been widely used and established in the industry for many years, offering a wealth of learning resources, documentation, and a vast community. On the other hand, UE5 introduces new and exciting features, including enhanced graphics capabilities, improved lighting systems, and advanced geometry processing. While UE5 is still relatively new, it holds immense potential for creating visually stunning and immersive experiences. It is recommended to start with UE4 if you are new to Unreal Engine. Once you have gained proficiency and are comfortable with UE4, transitioning to UE5 should be relatively straightforward as the fundamental concepts and workflows remain similar.