The most important number on a cricket helmet is not the brand on the back. It is the gap between the peak and the grille — the space a hard ball can squeeze through to reach your face. Modern helmets fix that gap so it cannot open on impact, and the ones that meet the current British Standard, BS7928:2013, have been tested with a men's ball fired at the grille and the shell alike.
Buy to that standard first and worry about everything else second. A helmet that carries the test mark against the ball you actually face has cleared the bar that matters. One that looks the part but predates the standard has not, however many internationals have worn its badge.
Fit is the next thing people get wrong. A helmet should sit level, grip the crown without pinching the temples, and stay put when you snap your head to duck a bouncer. If it slides forward when you look down, the grille gap you paid for has just moved. Try it on with your playing cap off, shake your head hard, and only trust the one that does not move.
The rest is comfort: ventilation for a long innings in the sun, a harness you can adjust one-handed, a weight your neck can carry into the evening session. Get the standard and the fit right and the helmet disappears — which, when the short ball comes, is exactly what you want it to do.