Ive got a Top Ten Olympia headguard. It doesnt have leather inside and its made from this soft rubbery stuff called bayflex.
Basically its the best headguard Ive ever had, loads of vision, doesnt slip at all really depending on how tight you adjust it (too tight and you will have some weird looking marks on your forehead for at least an hour afterwards lol)
Used to have a headguard with cheek protectors made from artificial leather, it would slip alot, restrict my vision (which I didnt realise until I got the top ten headguard) and to top it off it really ****ed with my skin, like irritated it.
If you can find a Top ten headguard in the USA Id definately get one.
The only thing I dont like about it is the chin strap can dig into my throat sometimes, but Ive got a massive adams apple so I think its just me.
Oh yeah lastly, you can get them with an AIBA sticker on them (costs like £15 extra event though its the same thing) so yo can use it in competition.