If you are happy with slow growth then yes, it is a very safe investment and will rise this year. However, do not expect massive growth as it has already been to the moon. You should invest in cheaper coins that will reach the same price as ethereum. Take a look at LISK and NEO, both of which are competitors to ethereum and will rise rapidly this year. LISK is cheaper, but NEO is already ready with ICOs - both are better investments for 2018
I think that LISK is one of the really good options, and NEO does not really like me. NEO is now in silent stagnation. I do not know what can stir it. The project is good, but passivates.