I would say that electra has a bright future. It is fast, cheap and with an attractive PoS rewarding system
I personally don't know anything about Xtrabyte but I have heard good comments about it
I agree with Electra. It's a very nice and very fast private coin. Market cap ist still low. When ECA is tradable at bigger exchanges, it will easily x10 - x100! A must have for 2018.
Xtrabyte is also a nice pick, but i would prefer ECA.