Loreal Hi color vs Goldwell Elumen , which is better?

Well, Goldwell Elumen is not a high lift color - it is deposit only like Manic Panic.  Loreal Hi Color is a high lift color that lightens your hair and then deposits a color.  If your hair is already lightened then there is no need to damage your hair with a high lift color.  Special Effects and Adore are very long lasting if that is what you are looking for.

Elumen is a weird one, it isn't a hi-lift or even an oxidative dye, it doesn't lift at all. It is slightly different to regular direct dyes in that it uses an acidic base to penetrate the hair.
Hi Lift dyes should only be used on virgin hair, so you could use on your roots and then top up with a good direct dye as it fades. Special effects or Adore both have great reds, and another one i have had great results from was Ion Colour Flash, their reds are amazing.

I don't have experience with Loreal Hi Color but Goldwell Elumen is as permenant as they get, especially if you use "Elumen Lock"  afterwards to seal it in. But as a warning, once you dye your hair with Elumen, it's almost impossible to ever remove, even with bleach and clarifying shampoo. So if you're looking to change your colour in future I would avoid Elumen and use another brand.

Also Elumen only really colours over a light blonde (10-12) base only, imagine them like a translucent dye. But the reds are ok, they look better over orangey hair, as over blonde/ash hair they go pinky.

My favourite Red's are Affinage Red/Violet, they class as a permenant but pretty much last the same amount of time as Directions do.