In general, blog commenting is good to build relationships, which then can get you links that pass value. However, in the short term, they probably do not help. You should build relationships with influencers in your space - however, it's not necessarily true they will come from inputting these keywords in Google's Blog Search.
If you're paying attention at all (you're running a startup in the vertical, right?) you should know who has influence. Start there, add value, connect - the links and secondary sites who may also be interested will show themselves organically over time.