To me the biggest difference between VidBlaster and Wirecast is the compositing. Maybe some people don't like the potential density/complexity in Wirecast. I go back to linear editing days with Grass Valley 300 switchers (actually before that but I show my age).

In Wirecast each shot can have 7 layers. Layers can be anything from cameras to screengrabs, video files, logos, audio, lower thirds, layers of all the above for picture in picture. That includes things like separate audio from each source if needed. All these "travel" with the composited shot.

In addition to that there are five master layers. They too can be anything. This allows you to separate bring on cameras, titles, transition between audio sources, etc. These might be somewhat similar to a VidBlaster module but not quite.

For me, the 7 layers shots are like Mix/Effects buses (keep in mind I have no limit to the number of shots). The 5 Master Layers are like "Downstream" keyers etc. These are titles and audio, etc that I can control independent of the shot that on air.

For example: I may have One 4 way PiP with lower third and guest audio, Then Three 2 way Pip with each guest and their audio and lower third. Then 4 solo shots tied to guest audio and lower third (except my shot). This is in one Master layer.

In a Master Layer below that I have my audio so I can bring it in and out independent of the other shots which the audio of the guest is tied to so their audio is gone when I cut away from them. I can keep my audio on so I can talk on air to guests even if my video isn't in the shot. In another Master Layer below that I have a background that all the PiP shots go over (and am free to change independent of the PiP shots. in an upper Master Layer I have lower thirds that go over my shot (they may change for various reasons, I can also use them to cover the lower thirds tied to the guest shots/PiP shots. All this might be hard to visualize.

In VidBlaster it seems I only have Master Layers (although many more than 5 though). That means things need to be brought on independently so I find I'm doing a lot more clicking around during a show. It seems a hardware audio mixer plays a much more important role.

VidBlaster does have some excellent features such as multiple screengrabbers, replay, built in playlist and Virtual Camera (which Wirecast finally has) but I just can't get the composite complexity and the ability to go from one shot (7 layers) to another shot (can be different 7 layers) like I can in Wirecast in as few clicks since I can pre build it in Wirecast. Granted many people don't do shows like that, hence my comment the density/complexity. Some people don't like it or need it. Some might prefer more modules than just 5 Master Layers feeling that forces you into pre building some things.