What Are The Best 12AT7's and 12AX7's?

Has anyone tried the Sophia Electric 12AX7's? I bought a pair of their 6SN7's for my Modwright LS100 and they are beautifully made and excellent sounding tubes, far surpassing the stock tubes that came with the unit. I'm considering trying their 12AX7's for my Herron but was wondering if anyone else had tried these--I see they are not mentioned so far. Also, one kind A'goner sent me a pair of tubes to try in my Herron. I haven't tried them out yet as I've been breaking in the Modwright. Meanwhile, we switched over to a new computer and I've lost his email. If you are out there please contact me and thanks again!

Thanks everyone so far. I'm currently running the tubes that came with the unit. Svetlana 12AX7's and Electro Harmonics 12AT7's. How do these tubes compare with some of those favorites mentioned? What kind of sonic impact can I expect from rolling in some of these other tubes. While I've got the experts assembled, is there any performance differences between the various Mullard 5AR4 rectifier tubes? For example, some are listed as f31 others f32 etc denoting (I believe) manufacture date. Which of these are considered the best that Mullard made?