I have founded 1 digtal marketing agency https://gotchalocal.com/orange-county-seo/ and designed two SAAS products http://cockpitmetrics.com and http://messagemetric.com which are coming to market summer 2015.
7 years experience successfully owning and running a digital marketing agency https://gotchalocal.com that has server hundreds to business from the USA and Canada. Produced over 10 Million in sales online.
If CUJO is your brand either will probably rank fine for that keyword. But in our testing .com's will rank better than .io's for non branded keywords.