I havent seen the eFX irl. It is however made of gf and therefore not good for trooping.
Judging from pics I think the eFX is the best licensed helmet. If you want accuracy there are fan made helmets though that are much better.
The MRCE is plastic and its symmetrical (as it would have been if they made ep4 today) . It will not look exactly like the asymmetrical movie helmets no mather what. On the other hand, if you like the symmetrical look, or want a nice helmet to a low price and arent to picky with movie accuracy thats a good alternative.
Cheers