Bitcoin is outdated? yes I have heard this many times before from those altcoin promoters that thinks their coin is better than bitcoin. But what happened to those that told bitcoin is outdated, they ate their words later.
Nano is also a good coin but to tell that it can be better than bitcoin, I don't think so.
XRB still young in the market, it must have a massive support system? It needs the high level of confidence by the consumer's investors? The fundamentals should be solid and a good market structure? all of this indicators need to be satisfied first by any coin posted in the trading market, My one cent opinion will go to Bitcoin, it is already tested in the market and remains stable even after the beating.
to my knowledge the State of many of the current coin has decreased. so it is risky to be potentially high coins to generate even more profits. so using a coin that could potentially be very lucrative. as present at the Cryptocurrency, a development owned by Stellar looks pretty good. and I think this to be the most suitable coin.