I'm guessing that the goal you are trying to achieve with your Blogs is to drive your SEO ranking up. If that is the case, I will backup Rolan on the fact that you would need a lot of content for each product to actually make it meaningful. I'm also guessing that if you are a startup, your product have to be in the same category or type of service. If they are not, you might want to consider rethinking your strategy to be more focus. It is important to be laser focus when you start a business.
My take on your question is: Have only one Blog, categorize properly and Tag properly to help Search Engine find their way in your blog and its content. Having one blog will increase the overarching SEO weight of you site and will benefit all your content.
If you really have very different product on very different subjects, then having different blgos can make sense.
hope this helps