While exploring if the support was there for a run, he's met with a lot of liberty groups as well as Tea Parties, and been interrogated rather thoroughly by them. He is against bailouts, the NDAA, foreign aid to our enemies, and supports auditing the federal reserve (and understands they cause inflation.) These issues alone put him miles ahead of McConnell. I think we'll see a lot more information coming after he officially announces.
As to his sincerity... I can only say that I have seen him stand up to groups of people whose support he needed when the situation called for it. From everything I can tell, he would be a solid ally for Rand, and though it's hard for me to be sure of anyone (Folks like Ron, Rand and Massie are rare indeed,) my trust has been growing for several months. He can go one about our Founders, which reminds me a little bit of Rand. Much better than those who inspire other politicians. So my analysis and feeling based on experiences so far are that he is not just "anyone to run against McConnell," but actually has potential to be a really good ally and candidate. At worst a Ted Cruz, but at best someone like Rand or Mike Lee. He's also got some Ron Paul supporters very close to him, which I personally find encouraging.
Last of all, he's a serious and methodical person. He knows exactly what type of challenge he is taking on, has a plan for achieving victory, and seems to have a decent appreciation of strategy. He's definitely going to make the race interesting. If anyone could pull off this upset, it'd be someone like him.
Here's a little more information about him personally:
http://mattbevinforsenate2014.com/2013/07/22/matt-bevins-humble-roots/
