Just a little more info for you to digest.
BMD only bookmarks and pings your sites - some major social bookmarking sites (but not many), pligg, and scuttle sites. And it is a one time purchase.
Senuke will bookmark and ping your sites on more of the major social bookmarking sites (but unlike BMD, you can't add to the list of sites), has a built in keyword research tool, will create accounts and post your articles on about 10 Web 2.0 sites (hubpages, wetpaint, associated content, wordpress, ....), will post your videos to video sites, has a built in article spinner (similar to Power Article Rewriter) and will spin and post unique articles to your 2.0 sites, plus more (but I can't recall anything else at the moment). Price - monthly charge of $147
So you can see it is not fair to directly compare them, it depends on what you want to accomplish as to which one meets your needs.