This review addresses some characteristics not expanded in the excellent and comprehensive posting here ("Try this paper just ..."). Writing applications are very well covered there. This is for those who need more information for their paper projects other than correspondence.
This medium is surprisingly brawny for such a thin paper. It stands up well to wet media (transparent watercolors, brushed inks), paper mechanics (origami, pop-up pagination, envelopes, Japanese fans and lanterns), and one-off prints (linoleum block, rubber stamp) for tipping-in by custom book makers. Wet media pucker occurs but relaxes when the medium dries, returning to a flat and dimensionally stable condition.
The paper does not dilute black into a gray by absorption resulting in an extremely pleasing contrast ratio. There is a high fidelity of wet and dry colors on this white. The high contrast between black and white makes this a perfect vehicle for any reproducible need. Very thin for intricate pin-point accuracy with swivel cutters. Minimum amounts of feathering and bleed through makes this paper wonderfully receptive to extreme detail in printing and manual artwork (specifically pen and ink).
The surface can be reworked after ink-jet printing and heat does not seem to change the texture or media acceptance.
Extremely resilient under repeated back-and-forth creasing (does not tear but hinges, instead).
Archival characteristics are unknown but this paper is impressively versatile for everyday use by artisans.

Try this paper just once if you want to understand why it has a cult following. It's lightweight (akin to airmail, bank, or layout paper if you want a comparison) so it might not be to your personal taste, but it's especially good with fountain pens and shows off FP inks to their best advantage, and with no feathering or bleed. (In my experience, anyway, and I use some very saturated inks.) I've bought a lot of Tomoe River over the last couple of years in both white and cream from various sources, both loose and bound into books, and it's never disappointed me. Despite being lightweight, it's robust enough to withstand hole-punches and daily use in ring binders; my bog-standard HP printer handles it with ease; it accepts inkjet printing well; I can make it into stitched notebook refills or glued pads; and it's a wonderful tactile experience to write on. Yes, it's delicate, so it rumples more easily than regular paper if you're not careful, and if you can't tolerate any show-through then it's not for you, but if that doesn't put you off, then you'll probably love this paper with a passion. I bought it originally because I needed a high page count without thickness, and everything else from bank and bible paper to airmail paper in the right size and colour was proving too hard to source, but now I buy it as much for the sheer pleasure of using it as its practical advantages. Treat yourself to a pack!

To those who wonder whether or not the paper is good for drawing- It is, but it depends on what you're using. The paper takes ink very well, but things like Copic markers or any other alcohol based marker don't get the even wash effect the do on regular paper. Also worth mentioning is that some inks change their properties on this paper. For example, the Zebra disposable brush pen is Copic proof on regular paper, but on the Tomoe it smears. So before doing any big project on it, it's better to take a separate sheet and see how the materials you'll use will act on it.
Other than that, the paper is actually great. No bleed through with inks, and the paper is somewhat transparent which allows to trace drawings :)

I love this paper! Paper is my thing. More specifically, writing on nice paper is one of my greatest luxuries, and I've found my favorite paper for writing with fountain pens. I write letters and also hole-punch it to go in my planner. I'm able to write on both sides of the paper with blue fountain pen inks and a medium nib. Though it does show through the other side, it doesn't bleed through, and I don't find it makes it hard to read both sides unless using a dark ink. Now that I've learned this paper works well for art as well, I'm excited to try painting on it.

Fantastic, magical paper. Wish it came with a dot-grid pattern (thus the 4 stars, should really be 5, though). The thin paper is deceptive, but no matter what fountain pen and ink I use with this paper, the characters are crisp with no spread. I've been making my own notebooks and 50 folded sheets of this thin paper produces a thinner notebook than 40 folded sheets of Rhodia.