@Crusher:
I am not a owner of the card, but I can tell you a bit I have read about it.
From a hardware point of view the card is constructed with more modern technology than the mediators. The only direct benefits from that is that the design is smaller, should draw less current and produce less heat.
From a software point of view the company - matay seems very open about releasing information. You will for example get software developer kit with your board and the Prometheus is supported by the OpenPCI library. Not like Elbox...
The only real drawback I can see with this card is that the physical fitting of the card and pci-cards on it might be a quite experimental experience if so to say

.
/Patrik