I am in the process of getting a few more certifications myself, and have been in the research department for getting certified. First of all, let me say that braindumps are great source for studying material, but you shouldn’t rely on them as your only source for studying. They usually provide questions that may have appeared on exams, but they don’t desrcibe why those answers are the correct ones and if they really are the correct ones. Furthermore, if you run into problems in the field answer A, B, or C will not be the solution. When taking these exams, you should fully understand what you are studying and should get a book that describes the information you are studying in more detail so that you grasp the concepts. Once you get the different concepts down you will be a better network technician or administrator.
For those interested in braindumps however, this is a great site, and most of the uploaded test examples contain explanations to their answers.
Let me note that you must purchase Visual CertExam Suite for a mere $20, but it is well worth it and can be used on multiple machines when used for personal use.