@Tom - most of the old negatives have been negated by Twitter not showing source of the tweet. Other apps do, and there's a very minor negative there, but not enough to stop using Hootsuite or any of the other tools for Twitter. The risk is to start using these tools for other networks. I use Hootsuite and Buffer for my own Twitter.
@Todd - tools like dlvr.it carry less EdgeRank power when posting to Facebook. They will appear lower than posts from Facebook.com or the native mobile app.