When you are traveling, you need the best resources for your trip. Otherwise you might waste time and money with bad resources that you might find online.
One thing you have to keep in mind is to see if the info is up to date. Many travelers have the unfortunate experience of being eagerly awaiting something only to find out that it is no longer there.
Local travel agencies actually make sure to keep everything up to date and have information that is more accurate. However if certain forums are alive and active, then forums are not that bad either.