My company does this currently. The upside is that the HTML is very configurable. (we have a rake task that generates a tumblr template from our rails app layout) The downside is that tumblr is down a lot more often that I'd like, and their API is down even more. Rather than using json-p to embed posts on our homepage we have an hourly job that tries to pull posts from the API; it only works about 90% of the time.

Also, when you set up your company blog, make sure you set it up as a secondary group blog so that you can have multiple authors. If you start it off as a primary blog you can't change to a multi-author blog later.