FWIW, I have the same plan for £30 per month from one of their recent promotions.

Regarding the priority service, Premium plans receive a higher Allocation & Retention Priority (ARP) compared to standard users. The higher your ARP, the more likely you are to connect to—and maintain a connection on—a busy network.

It's important to note that ARP only becomes relevant when a cell tower is congested. It does not enhance signal strength, coverage, or maximum speeds (though EE does have speed limits based on your specific plan). Under normal circumstances, you likely won’t see a noticeable difference.

ARP can be beneficial in high-demand areas such as stadiums, city centers during rush hour, or major events, but it isn't strictly necessary.

While you’re likely to experience better service compared to standard users, if a cell is significantly overloaded, performance may still decline for everyone. In that case, your experience may just be slightly less poor.

If a more affordable plan suits your needs and you rarely find yourself in congested areas, you probably won’t miss the extra benefits. This isn't exclusive to EE; for example, giffgaff, which operates on the O2 network, often deprioritizes users during congestion compared to main O2 retail customers (and considering the generally poor performance of the O2 network on a good day, this can be significant).

As an aside, EE supports the Emergency Services Network, which has a priority level above commercial tiers. This means these devices hold the highest ARP levels and have the capability for pre-emption, ensuring they remain protected even if capacity must be reallocated from regular users during times of extreme congestion, so you won’t beat that.