I thought "Cold Station 12" was a very good episode. "Borderland" was a mediocre entrance to the Augments arc. This episode put it into full swing. There was a lot of character development on the part of Soong and Malik. We see for the first time that Soong is not a monster, as it was somewhat assumed in Borderland. We see that Soong does have a conscience, as he tries to save the man locked inside the isolation chamber. He also didn't want Malik to try and kill Phlox. There is also character development with Malik. We see that he really is a psychopath. Even some of the Augments, ex. Persis, were shocked at his methods and that he disobeyed Soong.
There is not just charater development, but there is the introduction of Dr. Lucas, who Phlox has written several letters to. It was shown that Lucas was a man who was fairly unwavering. When the doctor was dying from the whatever blood burn it was, Lucas would not tell Soong the code to open the embryo's chamber.
There was also introduced an intensity that has not really been visited. The scene in which the doctor was dying was very intense, and, to my knowledge, nothing like that has ever been seen in Star Trek before "Cold Station 12". I was surprised that that scene did not get the episode a TV-14 rating.
An excellent cliffhanger put some icing on the cake. This was the best episode of Season Four so far. We'll see if "The Augments" can top "Cold Station 12".