Transformers are the key element for both SET and push pull. Even for OTL the power transformer is relevant. Likely the best commercial winders were in Japan in the late '90s, companies like HIrata Tango and Tamura. I think back then there was a focus on sound and quality rather than volume and profit margin.
Likely there are currently some good boutique winders, and maybe Western Electric were good (never heard an amp with these). Useful to distinguish between collectable and listenable - not sure where the WE falls.
I certainly do not equate 'high tech' with 'great sound'. Frequently the application of high tech results in additional complexity and worst sound. Hard to make the argument that the more you process the signal the better and more realistic it sounds.....