We've chosen to compare the EVGA's electrical performance to a PSU effectively a class up. The Corsair RM650 is a good example of a fully-modular 650W supply equipped with an 80 PLUS Gold rating. It also happens to cost £20 more, so you can determine whether spending that bit extra is worth it.
In terms of regulation, both supplies are very good. The key numbers to look out for are the full-load and cross-load tests. We'd be concerned if the voltage dropped to below 11.7V in either test, which it doesn't, and any big-name PSU of 2020 usually aces this important metric.
Put simply, the EVGA will deliver its entire quota of 550W without undue voltage drop.