As Hot and Hi says, wearing a helmet is a no brainer. The main benefits I see is that it saves your hearing and your eyesight. It saves your hearing on a daily bases and your eyesight for that birdstrike. If you are then unlucky and have an accident then of course it will help as well.
You can enhance your helmet with ANR which is expensive and it does work, there is another alternative though and they are CEPs, you can then save the money for the ANR and have equal if not better hearing protection using the CEPs.
I have only ever worn the Alpha Eagle 900, two across two different jobs, and they haven't given me any real trouble except the odd wear and tear. From what I can gather the Gallet don't fit every head unlike the Alpha's. The Gallet I am told need replacing every 15 years whereas the Alphas last only 12 years. I am told the Gallet are snug around your complete head, whereas the Alpha's have possible more air circling you head.
That's all I can add.
Companies to talk to are ses-safety.com or Key-se.co.uk or Helmet Integrated in Stanraer or headsetservices.com those are the only ones I know of.