Diablo v.1.1 has gold plated brass contacts. I don't have voltage meter myself, but on the finnish forum others have tested 0.26 drop to 0.9ohm, and 0.30 drop to 0.8ohm. Pretty good results.
And I agree, conductivity is one important factor when choosing right device with genesis style atty's. Especially voltage drop causing by bad switch contact can be really annoying - sometimes you get 3.2v, sometimes 3.7v, and sometimes even missfire... I rather take device with a good switch with ss-contacts, since you can compensate that with your setup and only thing that suffers is your battery life. And of course keeping everything clean helps too.