There's loads of differences.
Mediator comes in several flavours specificly made for that kind of amiga to fit it's formfactor where's Prometheus is strictly a Zorro3 "addon" card.
Where Mediator have the PCI slots in level with the backplanes of a specific Amiga model/tower and at the back where the backplanes are located the Prometheus has the PCI slots way inside the Amiga requiering extenders or an open case to connect cables to the PCI cards and the PCI slots are at an 90degree angle from the backplanes requiering either a custom built tower or PCI angle addaptor(s) to fit PCI cards to it.
Mediator have loads and loads of drivers available for several different hardware where's Prometheus only have a small handfull of drivers for few hardware.
Up til now Mediator is the clear winner BUT...
Prometheus is cheaper than Mediator.
Benchmarks show that the Prometheus is a bit faster than the Mediator.
Prometheus support OpenPCI so there's possibility for 3rd party drivers being made where's Mediator drivers are all made by elbox as no info of it is released.
Due to the above it's not possible to use Catweasel with Mediator but it is with Prometeus.
If you ask me I still preferr the Mediator over the Prometheus BUT it's only an oppinion and to be honest I wouldn't buy any of them right now but instead wait for the Dragon board to be released and look at that.
