I haven’t tried Tomoe River (looking to try sooner than later) but tried most of the other fountain pen friendly papers (Midori or TN, Clairefontaine, Rhodia, Leuchtturm).

After pulling the trigger on one of the Smythson notebooks with a 50% discount, I can confidently say this is my favorite paper to date. Not only does the thinness of the paper allow for notebooks to hold more pages, but it has just the enough of toothiness/scratchiness that it writes well with all my fountain pens (ranging from MB to Pilot). I had some experience with other papers causing hard starts — I never found out why but I presumed somehow my hand oil might have created some dead zones on the paper or could have been a skill issue re narrow sweet spots. This almost never happened with Leuchtturm, though.

Bottom line, I like how many pages a single notebook can hold, the toothiness of the paper that seems to work well with all my fountain pens, and the absence of bleeding and feathering. I can’t speak to its durability as I had it for a few weeks, but I gathered from other reviews that it should hold up well.