ETH doesn't look that high right now, if you didn't sell then I would say wait for another surge before selling. But it is probably better to hold for the long-term, because ETH really is a great coin.
ethereum does look a little stable for the past few weeks, I strongly agree with your opinion that we are better off waiting for a big increase at a longer time, of course if they (the traders) believe that ethereum is a great coin like you said.