As one of PCSTATS staffers is already the happy owner of a Prometeia Mach I, we'll be interested in seeing just how ECT has (or has not) improved on the original design. From the outset, the components are virtually identical, though the Mach II GT addresses many usability and cosmetic issues users had with the older models. However, the main development with the Mach II GT has been to replace the R134a refrigerant typically used to charge the compressor, with R404a.
According to Extreme Cooling Technologies, with R404a refrigerant the Prometeia Mach II GT evaporator head can reach a temperature -65°C under no-load circumstances. With an atypical 200W heat load, the cold head on the Mach II GT can sustain a -30°C evaporator temperature. Minus 30 degrees Celsius seems like such a nice temperature to run an overclocked Athlon64 4000+ processor at, don't you think? ;-)