It would be better to wait until the official build of 15.1 hits this week (tomorrow maybe?). The 4th Aug is an unofficial build and you’d then need to take additional steps to migrate to the official build.
When you do upgrade on the official build, you won’t loose any settings/apps.
This post contains details of how to upgrade ONCE the official version is available to download (don’t forget if you’re using gapps that you need to flash gapps for 8.1 before you reboot after flashing the new 15.1 build).