Jaaxy uses a combination of search engine data from the major search engines (Google, Bing and Yahoo) and Long Tail Pro get its search data from Google alone (via the Google Keyword Planner tool). While this seems to be an advantage for Jaaxy, you might only be interested in getting information from the number one search engine in the World: Google.
Keyword research is an activity you undertake every now and then. If you have a clear definition about the product or service you want to ‘sell’ with your website, you should be able to come up with keywords, related keywords, and even more related keywords to make your awesome website (more) findable. As your product and the market will evolve, your keyword strategy should do the same.
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).