Both are still at high prices. Eth can give one up to 30% profit, while neo - up to 50%. I would say that the safest coin and the one that will definitely give one 2x profit long-term (a few months) is bitcoin. However, is one is ready for some risks, it would be better to invest in ripple. I believe it can easily provide 2x-3x profit within a month, since ripple already was worth those prices. It is not a really risky investment like ico or shitty coin. Ripple is a strong project that is likely to become even more influential, whereas the price is still incredibly low.