G-Rex
- versions for A1200 and A4000 (&A3000)
- has lots of drivers currently for AOS3.x (gfx, audio, TV, 10/100Mbs network)
- will be supported in MorphOS if you have PPC-turbo
- there probably won't be much updates anymore for any AmigaOS
Prometheus
- only for Zorro3 Amigas
- may have PPC-turbo (G3/G4) in future
- not many drivers in AOS3.x (only gfx and 10Mbs network)
- driver development for AOS3.x has been extremely slow
- professional-look
- will be supported in AOS4.0 and in MorphOS, if you have PPC-turbo
Mediator
- lots of versions for A1200, A3000 and A4000
- largest user group (support)
- possibility of SharkPPC/SharkPPC+
- will be supported in AOS4.0 if you have PPC-turbo
- largest number of drivers which are in active development
All are quite stable with their current drivers.