If you want to work digital voice or digital image transmission and receive (SSTV), WinDRM is one of the programs that does both and it is freeware. There are several other programs that can work with the same modulation scheme.
Based upon current results from testing digital voice, I don't see this as replacing analog SSB since the signals have to be quite good in order to have adequate throughput. But you don't have to buy an expensive box such as the AOR product to experiment with this mode. The AOR product is not compatible with WinDRM although the claim is that it can work with a few db less S/N ratio.
Although WinDRM can not copy DRM SW broadcasts, it is based upon the DRM standard OFDM with multiple QAM modulation and appears to work better than the earlier RFTP protocol that was initially used for digital transmission. I believe that you will find this URL from Dave Jones, who is a very active user of digital SSTV to be useful:http://www.tima.com/~djones/DRMCOMP.txt
Actually, a program such as WinDRM can send any form of data, voice, image, or documents, etc. and the receiving stations have a way of requesting repairs of any missed blocks. In the U.S., hams are prohibited from sending data in the voice/image areas and this program does not get used in the CW/data areas that much. This is probably due to its width of several KHz.