Now that the dual exchange rate game is over, I think that booking a hotel in EZE is the same as booking a hotel anywhere else.... not sure there is a book on when its best to book. You can roll the dice in many different ways but in the end it seems that the old supply/demand game will do its thing.

No W is Buenos Aires... not sure what the equivalent would be, there are some theme hotels in town but cant help you much in terms of finding something comparable. Having said this, the local youngish crowd in EZE do not hang out in hotels so perhaps its irrelevant where you stay since you will most probably be leaving your place of abode to find what you are looking for in one of the bar/club areas of town.

Have a good trip.