Don't Install If You Can't Deal With Bugs
If you don't own a secondary device, and/or you hate dealing with problems, you should probably avoid Apple's iOS 11.4 beta.
In its iOS Beta FAQ Apple "strongly" recommends installing iOS beta software on secondary devices rather than primary ones. For good reason.
The iOS 11.4 beta is pre-release software which means it's an unfinished product. As such, it's riddled with bugs and various issues. Betas have also been known to brick devices.
Beta testers have encountered various iOS 11.4 beta problems. These issues include UI lag, problems with first and third-party apps, random reboots, severe battery drain, and issues with Bluetooth. You can check out a running list here.
Apple will continue to refine the iOS 11.4 update, but future beta releases will also be plagued with bugs and performance issues.
You might be able to fix some problems yourself, but others will require a fix from Apple. Some might not get fixed until the official update arrives.
If you depend on your device and your collection of apps to get through a day of class or work, you probably want to stay on official iOS software like Apple's iOS 11.3.1 update.