The Writer is the better of the two episodes, and really feels like the finale of the game.
The Bad: Graphics are aging, extremely short, no vehicle sections, nothing new added, steep price
The Signal was a continuation of the main game and showed Alan fighting himself in his story and not knowing why. Following the signal from Zane Alan must stop himself from killing himself in his story and to wake up to reality. The Writer continues this with Alan trying to reach the lighthouse and get back into the cabin to stop himself. The story is very strong, and answers some questions that you may have had at the end of the main game. The end boss fight also feels like a huge finale and feels like it comes to a nice close without a big open cliffhanger.
The episode isn't as combat heavy as The Signal, but has a lot more unique platforming and adventuring sections than The Signal plus it's not nearly as hard. There are more words you can burn up to create things in the environment to kill the Dark beings and these tend to be more useful and unique. There are no driving sections in this one unfortunately, but it makes up for it with more varied game play.
The Writer really mixes up all the elements in the Alan Wake universe very well and gives us one final shake up of all the things we're familiar with. This is what makes The Writer stronger than the last episode plus the conclusion of the story really helps as well. If you just so happen to have waited almost a year to get this you'll notice some minor things like the slightly aged graphics, but other than that this DLC is strong and solid. I still wish the DLC would introduce new weapons or something in here, but at least it doesn't recycle the same areas from the main game. The price is a bit steep even for something better than The Signal, but fans of the game need to get this to conclude the story.