I recently bought Long Tail Pro – a keyword tool that can find keywords and have a nice competition analysis using SEOMoz data.
In principle it is very nice, and according to the demo it is faster than Market Samurai. However, here it didn't work nearly as well as it should.
First of all, it asks for your e-mail and authorization key. That is OK – the first time. And then it continues asking, every time. Annoying, but certainly not fatal.
Then there is the keyword system, which simply didn't work here at all. It tried to get the keywords and never returned any result.
Competition analysis has some great data. My problem is that it worked a couple of times, and then simply stopped working. No error messages, nothing. Sometimes I'd press the button to start it, and eventually the button would be clickable again, with no results and no feedback.
There is also rank tracking, but frankly, I had very little interest there – it is easily the most common function (personally, I use Rank Tracker).
I'd like to note that after all these problems on a program I just bought, I just gave up. I didn't spend time pursuing the causes with support, because at this point I didn't think it'd be worth it. I just requested a refund, which was granted fairly quickly (about a couple of hours).
So if you believe my problems are rare or uncommon, well, at least you can probably feel safe about getting your refund.
Market Samurai has a bunch of tools for SEO and related fields. Please note that I've used the trial for this review (edit: I later bought the full version).
The tools available are Rank Tracker, Keyword Research, SEO Competition, Domains, Monetization, Find & Publish Content, and Promotion.
The Keyword Research works fine, albeit being limited to Adwords Suggestion Tool (AFAIK). It has several different fields.
Their Rank Tracker is fairly slow. Searching a couple of keywords on Google only takes more time than 50 keywords being searched on Google, Bing and Yahoo on SEO Powersuite's Rank Tracker. It does have interesting, different data on the domain.
SEO Competition shows a view of the competition for a certain keyword, with many important factors available per URL, such as PR, Page Backlinks, etc.
Domains make variations on domain names based on your keywords, and offers options to buy these domain (didn't work when I tried their option to buy on Namecheap). They also use DomainFace to offer aged domains, which could offer existing SEO value such as PR, backlinks, and also Google is supposed to “prefer” older domains.
Monetization finds products to promote from various affiliate programs, and allows generation of Dynamic Ads.
Find Content and Publish Content looks for articles, blog posts, videos and news for your keywords, and allow you to re-publish them.
Promotion searches for opportunities for backlinks. It is similar to the base functionality of Link Assistant. It does have more interesting search options (such as blogs, Yahoo Answers, PhpBB and VBulletin, etc), but seems to lack the tools for automated link requests and reciprocal list generation.
One thing I was quite impressed about Market Samurai is the number of videos (with good transcripts, which I really prefer for most material) they have about the program. There were a number of features I overlooked at first sight, but turned out to be very useful after they were demonstrated.
About the price, Market Samurai (US$149) is cheaper than SEO PowerSuite(US$249), and has free lifetime updates. I think they are both pretty good, and each have different strengths.
In conclusion, I'm using both SEO PowerSuite and Market Samurai. While they have many intersections, they also many different features that makes it worth the price.
If you can only afford one – go with Market Samurai. It is much cheaper and you don't have to pay for continuing updates.
It has a free trial (an unusual 12 days), so you can try it yourself.
Market Samurai 4 out of 5 stars
Update: Right now (12/May/2012) Market Samurai is very much broken, and a lot of the features related to Google won't work anymore. SEO PowerSuite still mostly works fine, but I can't get decent keyword recommendations anymore.
I'm downgrading my number of stars to 1 for the time being.
Update (18/Dec/2012): Rank checking is completely fixed, although limited for the free version.