The primary difference is that Long Tail Pro is a big time saver over MS. With Long Tail Pro you are able to enter in multiple seed keywords at once (rather than just 1 with MS). So, instead of entering in 1 seed keyword, waiting five minutes, then going back and entering in one more; you can enter 5 seed keywords (for example), hit generate and then see all the keyword ideas at once!
If you already create niche websites, you can clearly see how everything I’ve discussed above will benefit you. In fact, you probably already understood all of it. But maybe you are a blogger who has never thought of creating a niche website. Is this you? Let me tell you – if you can create a blog, you can create a niche website. It is not hard at all to create a small site, laser focused on a very specific topic, that will earn at least enough to make Long Tail Pro pay for itself.
Because I’m naturally leery of tools, I was very hesitant to make any snap judgments on Long Tail Pro. But after I read the reviews on the product and learned more about its seriously cool developer Spencer Haws, I decided to give it a go and made the $97 purchase. As soon as I started using the tool, I quickly fell in love with these two main features:
Using the good ol' free Google Keyword Planner is great. But there is an alternate universe of Long Tail keyword phrases that live in Google's other database--namely, their "Autocomplete database." That's the database that is accessed when you're typing queries into the Google search box (notice that list of suggested keywords that pop up as you type?)
Once I have a list of phrases, rankings, and volumes from these tools, I'll look to internal tools (maybe Excel, Access, or another database) to organize, classify, and forecast opportunity. This is where I'll estimate a competitor's traffic based on volume & position CTR, set goals for a target position, and estimate traffic based off that position's CTR and keyword volume.
2) SEMrush- This tool offers fantastic competitive research around domains to find what keywords could be driving traffic for your competitors. Looking at paid keywords ad spend can also help you know which keywords might have monetary value worth pursuing organically. If a competitor is willing to spend a high ad budget on terms and you think they do a good job running their ad campaign, then its a good indication it is worth organic ranking effort.
The “Starter” tier, with 1000 keyword lookups every 24 hours should be enough for anyone starting out in blogging – or even people who are quite established. It’s pleasing to see a product where they don’t seem to trick you into having to pay for a more expensive version. On the more negative side, I did feel that you’re nudged towards doing annual payment, with the monthly option kept slightly “hidden.”

WordStream for PPC is a full-service PPC management platform for creating, optimizing and managing pay-per-click advertising campaigns in Google AdWords. Our PPC software includes easy-to-use PPC keyword tools, campaign creation and expansion tools, Quality Score optimization tools, and more to help marketers get their PPC work done quickly and cost-effectively. WordStream for PPC customers experience increased traffic and greater ROI.

Analyze Keyword Difficulty – Targeting difficult keywords with the highest competition is not always the best idea. The SEMrush Keyword Difficulty tool helps you determine keywords’ difficulties. By indicating a particular keyword’s percentage of difficulty, this tool helps you estimate how easy it would be to seize your competitors’ organic positions in the SERPs.

TIP: A really good strategy for increasing your search engine rankings (and maybe even getting a featured snippet), is to pick a number of popular questions, and answer them in your content. You can do this in the form of a ‘Question & Answer’ section or maybe ‘FAQs’. Just pick half a dozen or so questions, and list them, together with a short answer.

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.
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).