What I miss in the comparison is the big difference in the way the educational resources and activities are organised for the students. (Derek, In your table it is hidden in the course assignment row.)
Blackboard uses a desktop metaphor: you get all kind of baskets on your desk: a basket with resources, a basket with assignments, a basket with forums etc..
You also need to write instructions like: "read this assignment carefully. Go to the resources and pick-up resource36352. Then go to the forums, selct forum 382622 and discuss with your friends the content of resource36352."
In Moodle you arrange resources and activities on the canvas of a section (on top of the section you place a title: the topic for that section, Under that title you place resources in a visual way, you can use the outline function of the section. Then on the correct places between the resources you place the activities: students see in a glance the educational purpose. (You even can integrate on a deeper level: if you use the filter mechanism of Moodle, you can integrate inside an activity multimedia resources, a simple flowchart, netlogo, scratch - or even a Simile timeline with a self created filter - in the same way as you use the chain symbol in Word.)
I use the free iSpring tool to publish powerpoint with spoken text. (In Slideshare and other online tools/stores you loose the sound option)
I advise not to use the built-in lesson tool to prevent lock-in: if you spend a lot of time in creating forked scenario's I would advise the platform independent (Scorm compatible) tool Xerte toolkits from Nottingham University: on the moment they are replacing the Flash parts with real html5 parts. (Have also a look at H5p.org for the creation of simple interactive resources like a movie with questions )