This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
The difference is about $50,000 per processor (or at least it was at one time).
I use BlazeDS because it is free but it cannot do all that LCDS can. I use Wowza for all RTSP because it is fantastic and a lot less expensive than LCDS. If you want to go all open-source (and have need for certain features) you can use BlazeDS and Red5 (in my case I have to stream video).