user2046: I am building a 2 camera, 4 mic webcasting setup. 
Using firewire to connect the 2 cameras to a laptop is more involved as it requires 2 analog to digital converts and 2 firewire ports, whereas most laptops usually have at least 2 usb ports.
I need the video quality to be good (possibly HD), stable and reliable.
Which route should i take?

user2047: For the best quality and/or High Definition you want to use the fastest computer input you have that your streaming app will accept. That would normally be Firewire. Most online streaming sites will accept both USB or Firewire.
Take a look at http://www.youtube.com/user/TEDxTalks/search?query=tedxsanantonio+2011. These are TEDx Talks we shot using a SONY PMW-EX1 with HD/SDI out and a few other SONY HDV cameras with SDI adapters ($200 each I think) into a Newtek Tricaster that was streaming and recording 1080i. The HD files were uploaded to YouTube.
Hope that helps

user3002: Firewire is better for video, because firewire is a more sophisticated interface. Firewire provides for device to device communication, DMA transfers and other performance features that USB does not. Therefore Firewire does not rely on the host computer's CPU. USB does not provide DMA transfers. All data on the USB bus must be managed by the CPU loading it down and potentially slowing the databus if the CPU is busy with other tasks. Since Firewire can keep transferring data without assistance from the CPU, it's better suited for continuous data streams, such as video.
Firewire does have a downside. Firewire interfaces are more sophisticated and therefore more costly. Firewire devices cost more. Firewire computer interfaces cost more. USB trades off performance and flexibility for low cost.

2046: <p>I am building a 2 camera, 4 mic webcasting setup. </p>

<p>Using firewire to connect the 2 cameras to a laptop is more involved as it requires 2 analog to digital converts and 2 firewire ports, whereas most laptops usually have at least 2 usb ports.</p>

<p>I need the video quality to be good (possibly HD), stable and reliable.</p>

<p>Which route should i take?</p>
 2047: <p>For the best quality and/or High Definition you want to use the fastest computer input you have that your streaming app will accept. That would normally be Firewire. Most online streaming sites will accept both USB or Firewire.</p>

<p>Take a look at <a href="http://www.youtube.com/user/TEDxTalks/search?query=tedxsanantonio+2011" rel="nofollow">http://www.youtube.com/user/TEDxTalks/search?query=tedxsanantonio+2011</a>. These are TEDx Talks we shot using a SONY PMW-EX1 with HD/SDI out and a few other SONY HDV cameras with SDI adapters ($200 each I think) into a Newtek Tricaster that was streaming and recording 1080i. The HD files were uploaded to YouTube.</p>

<p>Hope that helps</p>
 3002: <p>Firewire is better for video, because firewire is a more sophisticated interface. Firewire provides for device to device communication, DMA transfers and other performance features that USB does not. Therefore Firewire does not rely on the host computer's CPU. USB does not provide DMA transfers. All data on the USB bus must be managed by the CPU loading it down and potentially slowing the databus if the CPU is busy with other tasks. Since Firewire can keep transferring data without assistance from the CPU, it's better suited for continuous data streams, such as video.</p>

<p>Firewire does have a downside. Firewire interfaces are more sophisticated and therefore more costly. Firewire devices cost more. Firewire computer interfaces cost more. USB trades off performance and flexibility for low cost.</p>
