ETH is in a very tricky situation right now. It's probably too late to buy early, too early to sell if you bought back during accumulation, and ETH/BTC situation is unsure (currently around 0.04btc) which can, or can not be reversal point. I think this trade depends mostly on your position (trader, swinger, investor)
The 3 points
Catalysts : currently, it seems everyone talking about ETH in wide public is either a fanatical pro-ETH almighty about a paradigm shift of smart contract, blind to see it is not the only one anymore, and might get it's market eaten by others. Or about the infamous ICO scams and potential bans sooner rather than later (speculatively, governments are slow, especially if some officials are invested personally...*kof kof*). Its council's ethics and recent hacks are at least questionable
Fundamentals : its code and vision are impecable, even if it suffers from insane scaling issues right now. Future updates, if well made (and sentiment is that devs are very capable), has a big chance of making ETH one of the main aspects of internet 2.0 in the long term. The future PoS switch from PoW will also make a lot of FOMO from new blood (old blood already have it priced in, IMO)
TA : same as XRP (both charts look alike), with a classic ABCDE contraction phase. However, D and E points are rather blurry, and makes the analysis a lot less predictible and overshadows a rather cautious view in short to mid term from the market. As my friend piptocurrency likes to say "the biggest the marketcap, the harder they fall". Eth might just have not fell or consolidated enough just yet
Overall
Trader : wait for bullish confirmation of ATH with big volume, and get in at pullback 401$, with constant distribution of gains up to psychological of 500$, then look for better entry. sl at 390$ for fakeouts (few days)
Swinger : buy orders at 255$ and 290$, sl at 250$, or buy breakout with strength, SL 390$ TP 600$ for bullish projection minimum target (couple of weeks, probably by february 2018), 800$ max for last TP before correction
Investor : com'on, it's ETH, you are already in since long ago, TP depends on fundamentals about adoption from non block-chain developpers (using known C# or java has better market penetration than solidity) and PoS implementation. However, now might be a good time to take just few % to invest into ETC. Wait 400$ break or 255$ to add more
In the end, the smart money should not only look at potential upside or downside, but the cost of opportunity. How much would have you made with your money on BTC, NEO, or some of the others, lower marketcap?
Still, ETH/BTC chart shows that now is a good time to open a small position to accumulate btc in the longrun, but more down is seriously possible. ETH/USD investor should not worry for the longterm, even if we are hit by a crypto-winter