The kevlar is nice and light but it cracks and looses most of its protection. I have the PASGT, and just need to note that you might want a strap replacement as the stitching on mine popped, you can also cook in it, but note that the stainless steal clips etc.. can rust if they aren't upkept. No idea about the steel can but I would think it is way thinner than the pasgt, lighter too. None the less I got the PASGT (israeli make). There are newer helmets though. None the less I think you will look less serious with the WWII helm, while the kevlar imo is a single use item, you can get away potentially with the PASGT for multiple usages, bear in mind that you might want to upgrade and get more internal padding. Just bear in mind they aren't designed to stop high power rifles, so hopefully you are facing someone with an AR or other sort of mid to low calibre. PASGT are rated 3A i think while wwII helms are at best flak helms and rated perhaps a 1 or 2. The kevlar is also 3A I think however it is not rated for multiple rounds, PASGT may be deformed but it is rated for multiple rounds. I also think kevlar cracks and is susceptible to loss of capacity over time, and is sped up in degradation by UV light so unless you have a fabric mount that shields it from light its serviceable life is reduced. An older kevlar helmet that has been left laying around is not serviceable with any margin of certainty. I would be very unlikely to use WWII equipment if I had post gulf war equipment to use with very few exceptions.
pasgt is an awesome prepper pillow.