As you can see, LongTailPro is pulling data from Google Adwords. WHAT?! So LTP uses a mix of their own massive data (launched in 2011) and data pulled via API from Majestic.com, Moz.com, and Google Adwords (http://adwords.google.com). Once you input your seed keywords, LongTailPro outputs suggested keywords related to your seed keywords, search volume, Adwords suggested bid, Adwords competition, total words, rank value, average keyword competition, language searched, and location searched.
1) SEMrush - I believe that among all the 3rd party software, SEMrush has the largest keyword database. Their search volume data is pretty accurate and aligns with the Google keyword planner. Also, based on the type of content that needs to be produced (i.e. informational, transactional, etc.), one can utilize different filtering options available in it.
It arranges your search volume by separating the relevant keywords from those considered irrelevant. It presents those keywords, which it believes would help rank your search engine very high. Once you indicate that you want your keywords to be filtered, the tool would help to arrange that. You know that is very important for your Adsense and adwords campaign. The program is relevant for your CPC and other internet marketing strategies that you want to use.
In Keyword Planner, formerly known as the Keyword Tool, you can get search volume and traffic estimates for keywords you're considering. Unfortunately, when Google transitioned from Keyword Tool to Keyword Planner, they stripped out a lot of the more interesting functionality. But you can make up for it a bit if you take the information you learn from Keyword Planner and use Google Trends to fill in some blanks.
There is no doubt that there are various keyword research instruments out there, however, many people were often disappointed with many of them because they fail to deliver the expected results. While some of the tools proved to be helpful when you look for specific niche keywords, others were simple failure. You would discover that as time goes on that, it begins to slow down. This affects the efficiency and the speed. This is not the case with Long Tail Pro. It does not only deliver efficient and reliable search results, it does it very fast. You would appreciate the efficiency of the tool when you have watched the demonstration videos and tutorials.
In a nutshell, Long Tail Pro helps you quickly find keywords in bulk based on a seed keyword that you input. In addition to returning hundreds of related keywords, the tool also shows search volume (monthly search volume), advertiser bid, number of words, rank value, and my favorite Keyword Competitiveness (helps you judge the competition and keyword difficulty).