The community aspect is actually what drives so many people to the idea of flashing custom ROMs, as there is a lot of active support available for custom ROMs and their users from volunteer developers. Being one of the most popular operating systems nowadays, there are lots of people actively engaged in the Android community and constantly sharing tips about how to get more out of the OS, what ROMs work best for different needs, and so on.
One more thing to consider is keeping the operating system always up to date. Sometimes the official releases of Android aren’t properly tested and can work quite poorly on older devices, much to the frustration of their users.
This was even a problem with one of Google’s own devices, the Nexus 7, which wasn’t quite up to the task of dealing with Android 5, and many people called it a mistake to make that version available for the device. Still, there are alternative solutions available although admittedly none of them are ideal.
When using a custom ROM, this doesn’t have to be a problem – the user can easily install an older version of the system if the new releases are running sluggishly and they are not limited to the main update channel by Google. Furthermore, custom ROMs are typically additionally optimized to make sure that they offer good performance and that they work with the devices they are intended for.