Well, Vox Populi is new (so no track record), and they are a GOP firm formed by major players like Cheney’s lesbian daughter.
Here’s an article on them
http://www.politico.com/story/2014/04/gop-polling-firm-vox-populi-polling-mary-cheney-105850.html
Here are the full poll results
http://dailycaller.com/wp-content/uploads/2014/05/Oregon-April-2014-Full-Results.pdf
Interesting that they don’t bother to poll Jason Conger against Merkley. Clearly they are part of the Wehby hype train. Mitt just endorse her.
It may be a small thing but I noticed that the poll questions do not identify the incumbent. Maybe that is standard procedure in polling. Maybe not.