It kind of depends on how your planning upon using it. If you are looking to mix or switch. I currently use a Videonics Mx1 which does a pretty good job if your just working with composite or s video and not keying over multiple sources. I also use a switcher scaler made by Hall Research TVB-200. Good for switching but not mixing.
I was looking for something more. Firewire inputs and recording to a removable drive are some of my biggies. I've looked at Wirecast
www.varasoftware.com and Livid Union
www.lividinstruments.com but looks like i would have to move to Mac to get all the features i need. Both of those are under $500. Would like to be able to afford the Tricaster or VT-4 but thats not in the current budget.
So many choices, so little time.
Video on!
Brian Ross