Miquelrius A5 notebooks are my everyday notebooks, because the paper is interchangeable with the paper in my A5 Filo. I especially love the plastic-covered ones (the cardboard covers are too thick and stiff for my taste), designed by Agatha Ruiz de la Prada.
The only drawbacks are the expense -- US $7 or US $8 per book -- and limited availability. I used to have to go to a large chain bookstore or The Container Store to find them. Imagine my surprise when I found them at the Fed-Ex Kinkos store just a few blocks from my house!
This Kinkos has increased its office-supply and book stock and cut down on space devoted to self-service copiers and computers. I guess they've decided they make more money from retail sales. In addition to Miquelrius in A5 and A4 sizes, I also found Mead notebooks and composition books (well made, but the paper is way too thin), Cambridge notebooks (Mead's high end), Black and Red notebooks, and a rare (in the US) A4 Topps notebook.
I bought 2 each of the red and blue patterns shown here, plus a dull, professional pinstriped one for work. I wanted to buy them up to encourage the store to continue carrying them.
I still can't find Miquelrius A5s at less than $7, but I figure it's the price of a glass of wine in a nice restaurant, or 1.5 glasses of wine in a lousy restaurant. Well worth the price, since I can use each notebook for a couple of months, while the wine lasts me maybe 1/2 hour per glass.