I think BTC is undervalued and ETH is overvalued at the moment. Bitcoin has seen a solid rise since 1014 and is just a little bit more than doubled since the previous ATH. Furthermore the scaling debate has pushed the price down over the last years. Also the mainstream media is always negative about BTC, while ETH is hyped. I think many people underestimate the strength of 2nd layers on BTC after Segwit gets finally implemented. This could suck all the money invested in alts back to BTC.
ETH is for sure very interesting, but more than 15 times rise in price after it's previous ATH is a lot and the security of the ETH blockchain is a joke. Further I expect scaling or security problems to pop up in ETH and seen the recent rise in price there is not much needed to cause panic = crash.
Also RSK is coming soon and could be serious competition if their promise is true (faster, cheaper and more secure).
I will sell half of my ETH for BTC and keep the rest for long term.