A possible disadvantage is having one of the target Search Engines return a bunch of bogus or secondary 'hits'. On the flip side, if two or more search engines return the same information, the Meta-Search Engine will only present one of them. No matter what type of search engine or syntax you are using, you will undoubtedly receive many secondary hits, and sometimes bogus hits. Many of the hits deal with groundwater, and other issues. Relevant, important hits are probably buried far down in the list.
User notices hotels and fitness centers are in the list.
A Results list of 20 is excellent. It will probably contain what you are looking for. Summary and Lesson Plan 1. Understand the Concepts. Learn and use Boolean search techniques.