What Step-up transformers are best value?

I can vouch for Fidelity Research FRT-3G as excellent and very musical transformer for its price. Very versatile.

If you want a great value check out choiraudio dot com. They have a Cinemag based SUT for $349. It's in a nice enclosure with star grounding. Unless you build one yourself I have not seen a finished Cinemag based SUT at this price.

The usual disclaimers apply - I do not have any financial affiliation with Choir Audio.

K&K Audio makes a nice one using Lundahl transformers

another vote for Hagerman Piccolo, in the bargain category. Solves a lot of problems that SUT's have.

Ultimately it will depend on how it interacts with your cartridge and phono pre. In my case the silks outperformed the S&B's. Unfortunately specs and reviews rarely tell the whole story of how an sut will perform in a given system. It would be nice if you could get an evaluation period when buying some of the higher priced step ups. Bottle Head amps are supposedly going to offer an SUT from magnaquest that should be very good and priced reasonable.