I think 350~370$ is a good buy for ETH. It has a good support for 330$ for a very long time.. you need to wait for correction, now you do not need to buy.. 400$ very expensive..
Consider about there will be a little correction and that should be a nice rate to buy ethereum as far as i understand. The reward for every block in ethereum already decreased to 3 ethereum for each block.
Soon the reward will be around 1.5 for every block.