I've been using a debugger based on the USBDM project. http://usbdm.sourceforge.net/ Same performance as PEMicro's $300 Multilink + $200 GDB Server. And no restriction on using them for production.

Been thinking of open sourcing the board I designed. The only real issue is, needing $1500 to pass FCC licensing since it's designed to fit in a case.