BTC will reach new ATH in the 1st Quarter as will most altcoins. I personally believe that 2018 is going to be far better than 2017 for all cryptocurrencys.

It is easier to make huge returns off of the lower market cap coins than it is off BTC, Eth, Dash etc. But you need to be very careful and watch the trading volume of BTC for the altcoin. A coin with a BTC trading volume in excess of 1000BTC in any 24 hour period is safe. Anything below that starts getting risky. As an example an altcoin with 20BTC trading volume in a 24 hour period only needs a few BTC spent by a whale and it looks like the price is rocketing up. The whale starts taking his coins out at huge profits and once the initial fomo from Joe public subsides you are sitting with hundreds of thousands of coins with no buyers due to low volume, next thing the price crashes again as everyone starts trying to get out. That scenario plays out every day in this market.

I think $5K to $10K for ETH this year is very conservative. That is probably the minimum you will be looking at.