Discrete low to hi Z transformers for Mic input on a budget

I've been fooling around with my old Shure M67 four channel mixer. It sounds pretty good really. It lacks headroom and has too much gain in some circumstances like micing drums. I like the fact it plugs into the wall with a permanent power cord, has a master VU, mic input transformers, and individual master and channel volume controls. I also have a place in my heart for discrete preamps and their low noise characteristics. However, I'm thinking of gutting it and addressing the shortcomings with a new PCB of my own design. I would improve the dynamic range by using the 34volt PS that's present rather than the 14v one it uses. Also ESP has published a lovely two transistor preamp with great noise/gain/distortion figures. It requires a mic input transformer to get the gain up to reasonable levels though and to be noise free with long cord runs.
I would reuse the transformers already in the M67. I have no clue how they rate against modern types.I can easily check the bandwidth with my signal generator and O-scope. When do they saturate is another question. I suppose I could check that too by overdriving. Apparently the sonic gurus like the sound of mic input transformers for the compression affect.
On the other hand I could leave that piece of vintage gear as is and remake the whole thing using a mic input transformer available commercially.
Looking at mic input transformers I'm bowled over by the prices.
Neutrik advertises a mic input transformer, the NTE10/3. It's only ~$15.00, a far cry from the 3 to $500,00 you can pay for others.
Anyone have experience with it?
What's so special about the expensive types?
 

Specifications Neutrik NTE10/3​

  • Audio transformer 1:3 (1:10)
  • Impedance ratio: 200:1.8k (200:20k)
  • Source/load impedance in Ohm: 200/10k, (200/50k)
  • Max. Input level (@ 50 Hz, 1% THD): -7 dBu (-6 dBu)
  • Applications: general purpose mic input step-up