Yes this is true that at this time crypto market is on their knees but no need to worry up and down are the part of the every market so at this time you need to be patience and market will recover soon and you will get excellent rewards.
I think at this current period crypto market is down and all alt coin also are low and it is for some time so you can invest more at this time but i will go for eth and btc these are the most profitable coins and these will definite give you a excellent profit in few months.
Ethereum and ripple bote are very powerful coins and they had proved it. But i like ethereum because it 2nd most valuable coin in crypto market and people trust ethereum most after btc.
is If you want to invest at this time My suggestion is go for Ethereum because at this time Ethereum is very very low levels and if you invest in that you will earn excellent profits at the end of 2018.
Today crypto market is a very huge market in the world and it is spreading day by and people are taking lot of interest in this market and it very profitable market so for take profit people are creating coins and coming in the crypto market.
I can not say exactly but i think ethereum is at their lowest price because the whole crypto market is down even btc is also is their low levels so Ethereum is also very low with the effect of all coins.