I must say I've dealt with HSL at Shoreham on a number of occasions over several years and always fond them to deliver excellent customer service.
I wear a Mil Mk10 (cos I have one and I'm used to it) and also use ALPHA Eagle for some of my flying. I used a gentex for a few years and found it rather flimsy and very sweaty in the hot weather.
Mil helmet is serviced by the Mil and the AlPHA is serviced by HSL.
Happy landings
3 Point