Hi,
I definitely believe Google that these won't be treated as country-specific domains, and if I were offered a keyword.co versus a keyword.info domain, I'd most certainly go with the .co. I think that it will resonate with people due to being similar to what they're used to seeing. This, of course, has nothing to do with a technical advantage: we'd like to believe that a TLD doesn't mean much from the perspective of a search engine, although you do see .com keyword-rich domains ranking better than other TLDs with the same keyword, in a lot of cases. Again, you don't want to confuse cause and effect: does the .com really help, or are .com domains usually owned by people who put up better websites? Hard to say.
When big companies use a TLD, that certainly lends some credit to it, and I think the domains you've bought are good. I don't think you've wasted your money, especially if they were quite cheap!
I wouldn't spend too much time or money buying every .co. domain under the sun, but I do think they're a better investment than many other TLDs. I don't have any stories of big successes yet, and I'd go as far as to say that the TLD is a bit too new to know what its fate will be. I do, however, doubt it will become as highly spammed and disregarded as the much-maligned .info and .biz.