A friend brought me an Ortofon ST-80 SE step-up unit for comparing it to the in-built SUTs of my EAR-912 preamplifier. Hmm... could there really be anything here?
My friend offered me to have it some days, and for three mornings - with fresh ears - I sat down and went through a wide range of recordings with the Ortofon Anna D hooked up to the ST-80 SE connected to my EAR-912 with MM setting. I used SILVERCORD PLUS Pure, solid OCC Silver – StarQuad cable - 1m - RCA-RCA from Yannis, Aberystwyth (eBay).
This was a difficult job as some recordings clearly had an advantage of the ST-80 SE and others not so much - if anything. What made the difference was mostly in the top octaves, where the ST-80 had a bit more resolution and better transient attack, again not much, but noticeable.
I couldn't help thinking this SE-80 was especially made for the Anna D as for my MSL cartridges I preferred the EAR-912 trannies. But the MSL cartridges have a slightly more energetic top octave compared to the Anna D, which appear overall slightly more balanced. 
The ST-80 SE has a single primary winding, where the EAR-912 SUTs have 3, 6, 12 and 40 Ohm windings. Maybe this is one of the things that makes it so well suited for the Anna D. In comparison my old Ortofon T5000 silver SUTs fit the MSL cartridges better with its slightly more mellow tone.
Bottom line is that I ended up buying the SE-80 SE. If there is more to have from the Anna D, then I need it, albeit not for every recording. These trannies are like seasoning a stew and having a selection makes fun.
Download ST-80 SE  brochure. Download userguide.