My employer provides helmets and flying suits for the pilots our choice and I went for the Gallet LH150 after 10 years with an Alpha and prior to that a Gentex SPH4.
In my opion the Gallet is far superior to the other products and the service from Trevor Norris Flight Helmets Australia was very good.
The noise attenuation with the Gallet probably isn't as good as the Alpha but that is easily overcome with the use of foam ear plugs.
The Gallet for me is much more comfortable (no pressure spots like the Alpha) feels more secure and has less wind noise when long lining.
I have heard however that it may not be crash worthy certified like the Alpha's maybe somebody can confirm or deny that.
Ask around what people are using and their reccomendations this is the right forum for that info.
Fly safe