I'm using the services of CrowdfundingPR (Silver pack, $50) and Ayudos (Basic, $60), and I would recommend both.
My press release published on Crowdfunding PR is currently in the top-10 sources of traffic to both my blog and my project page. As to Ayudos, they responded to my email very promptly, recommended a range of associated web resources to promote my campaign for free, and sent a free ebook with crowdfunding tips.
The one leading my campaign on Ayudos is Mike Gonzalez, the CEO. I asked him to write a better press-relase than mine was. There was no response for a week, and I was about to remind him of myself when I saw his article about my campaign featured on their main page (http://ayudos.com/
)! On the same day, it was also published by Wallstreeter Crowdfunding News.
Salvador Briggman, the CEO of Crowdfunding PR, is regularly sending me updates on the media contacted. During the first week of my campaign, they sent my press-release to 5200 journalists, 600 of whom viewed it.
I don't think I'd ever have time to find and contact so many media representatives myself, so I'd rather transfer it to those who is an expert at it and focus on promotion via social nets and forums instead. The guys from Ayudos and CrowdfundingPR don't really charge much, and I suppose they are much better at contacting media than I am. They do it on a regular basis and are known there, while I am not.