What's the deal with Tomoe River paper?

Tomoe River is famously thin (52gsm or 68gsm) yet handles fountain pen ink with minimal feathering and showcases ink sheen and shading better than almost any other paper. The catch: it's translucent, dry times are long, and reviewers note the paper was reformulated when the original mill stopped production, so newer batches don't always behave like older ones.