I had two JD100s as well. One of them came with Sovteks and the other had no lettering on them at all (although they sounded just like the Sovteks). The Sovteks were ok but lacked transparency. Electro Harmonix were the best of the new tubes I have tried. I ended up using NOS GE 5751s however - well worth the money - but the EHs have excellent detail and HF extension which I felt the JD100 benefited from.
Arthur
Arthur