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You have to bear in mind that rankings fluctuate quite a lot, particularly in certain verticals. I think the GWT rankings are 'averaged' and the SEOMoz ranking is likely to be a snapshot of whenever the tool last checked the rankings. You've also got to consider location, data centers and personalised search - try doing a manual search on Google, making sure you're signed out of any Google account and social media accounts, and adding the parameter &pws=0 to the end of the search URL. You can also try an external tool like seoserp.com. Hope that helps!

Sites that work hard at Web Accessibility often reap large SEO benefits. If you think about it, search engine crawlers have a pretty limited view of any give web page.  They can't see the images.  They work mostly by indexing text strings and ignoring large components of any web pages presentation. There's a ton of simple tips for accessibility that help with SEO.  For instance, add captions to your images and create navigational components out of HTML lists. Google's SEO Guide touches on Accessibility The W3C has Accessibility Guidelines for HTML which is also worth reading.

Interesting read, lets hope people see that before handing money over.

If you don't have proper pure HTML links, search bots can not be guaranteed to be able to properly crawl the site & discover all the content, search algorithms are less likely to be able to properly assess content relationships.  Proper HTML is fully capable of providing accessibility - it's a core function of HTML based navigation. If someone needs to use alternate means of navigating beyond a mouse, it's those very pure HTML links that are most likely to provide functionality to special browsers designed to meet accessibility guidelines.