Both coins are good and promising but for me, if I am your friend I'd prefer it if you will give me the Cardano. But to be fair, I don't know whether your friend thinks the same so I cannot answer for him/her. Also, make sure that your friend knows about crypto first if he is interested in it because it will be nonsense if he/she doesn't know a thing about either of the alts you are thinking of giving. Also, to be sure why not just give him half of Ripple and Cardano so he/she can have both. Two is better than one anyway.