The Hello I'm local is a really good place to stay either if you want to make a quick stop in Haarlem (like I did), or you want to explore the north holland province. The personnel is really friendly and willing to help in everything they can.
It's is very good located, just at a 10 minutes walk from the center.
The rooms are very spacious, comfortable and quiet. There's no TV, and the wifi only works in the common area. Although there's no parking, the personnel indicates you directions to open air parkings just at a 5 minutes distance of the Hostel.
There are several options for breakfast if it's not included in your room price, at a reasonable price.