Disci ? Holu?

What is more newbie friendly for early RHC etc? Disci or Holy?

I'd suggest you try both and see what suits you depending on what you want to play in the long run. Imo it's better to start learning how to manage crisis situations earlier in the game.
What I would add tho is that you keep in mind the difference between both specs, so disc being more of a damage preventor, per se, and holy being a killer healing machine.