Mobility Pros and Cons
One major plus of video conferencing is that you can set the camera up to show whatever you want. With a PC and a connected camera, you can use a tripod or other mounting device to stabilize the video and focus anywhere. With the iPad, this is a little different since the cameras are built-in. You'll need some kind of stand or mounting device to hold your iPad still, otherwise you might give the other users a headache from 'shaky camera' viewing.
iPad video conferencing is best suited for the individual user, rather than a conference room. The reason for this is simply because iPads are designed for use by one person and not really suited for a room full of people. A variety of companies already make excellent motion-tracking cameras which can be mounted in a fixed position and will then move around the room to focus on whoever is talking or moving. To get the same effect with an iPad, you'd have to pass the tablet around the table.
On the other hand, being able to carry the iPad around could be perfect depending on what you want to do. This would be excellent for showing off products to outside viewers. For example, a builder could do a walkthrough of a construction project using the iPad so that everyone can see how things are progressing. It would be helpful in a support capacity where you could show the problem in real video and get suggestions for how to fix it, like computer hardware issues or even mechanical problems in some industrial capacity. Instead of taking photos with your phone and waiting for them to email, you could do real-time video.
You could also carry around a laptop with a built-in webcam, but you'd have to hold it facing away from you. Also, the iPad 2 has much higher resolution video cameras than what you'll find on most laptops, plus it's front and rear cameras let you see what you're filming much more easily.