I think the ones posted in the pic by kitehard are probably safest. I wear a BMX helmet that is similar to the Ace Wake helmet. (use it on the pushie too). I actually bought a gath after having my tt get picked up by a barrel and spear into the back of my head causing stars, **** loads of blood and a nice big scars. (on an empty beach too so was lucky it wasn't worse, had to get in, pack everything myself while the white sandy beach was quickly turning red and brown with blood.)
Guy who sold me the gath said everyone buys them AFTER and injury. haha.
Anyway, don't like kiting in it at all. visor gets scratched by sand, so never used the visor, ear pieces whistle like its a cyclone from 12knots up and its a hassle to wear sunnies with it as there is no room for the arms, unlike more padded helmets. I reckon the 'disclaimer' about not being suitable to protect from impact or what ever it says is valid because there is only like 2 or 3 mm of padding and becoming unconscious in water is of coarse SOOOOOOOO much more scary than on land for obvious reason. my pushie helmet is perfect for me.
For the safety conscious:
Its said that the bigger wider floatier helmets pose more of a threat to neck injury when impacting with water, which makes sense but I'm personally a bit dismissive of this potential risk as haven't gone close to hurting my neck from this sort of situation yet.
Smooooth holeless outer shells are the safest for falling off anything on land, assuming its padded. This is due to the increased strength of the shell and the lack of snag points for if you slide. (The expensive, light aerodynamic, vented type pushie helmets are ****. (for pushies too) They are made to minimum safety standards with focus on weight and ventilation etc.
To conclude this essay...
If concerned about consciousness get something padded. If you are concerned about cuts only and kinda liked the Mighty Morphin Power Ranger look, go the Gath (but not the one you currently have, its ****. you need to up grade to this awesome one i just happen to have for sale)