It depends on how knowledgeable you are on the subject already. I just took the test last month and passed, but I did what they recommend you not to do and only relied on taking some practice exams to get an idea of what they ask on the test.

If you understand the general ideas behind the whole process, the points, and the certifications then there's no worry. It's a very broad exam. Honestly, there's enough information on their website as well as other places that I think some expensive study materials aren't necessarily worth it. But everyone takes tests differently. Any personal advice you'll get about it will be what worked for that person. Do what you usually did to pass tests in the past.

If you read through one of the big study guides they recommend you should be able to pass with a margin of safety. Shouldn't take you more than a week or two to do either. I would recommend doing that though, because as broad as it might be, there is a lot of content that is pretty insular to LEED, and I think not-studying that material puts you at risk for failure.

That said, it's really not a tough test at all.

I took the exam last month and passed, and would second all of the comments above.  I used the study guide and practice exams offered by GBES.  I've also heard good things about Poplar Network.  

The practice exams were by far the most helpful resource in memorizing the most important material.  The material is broad, but the exam is easy if you are studying the right stuff.

Wow. Appreciate sharing your insights and great advices. They are very helpful :) Thank you so much.