Yes, the paper is nothing to write home about! I bought a small one, useful - but it has not inspired me to do anything more than plan my next headfi-related purchase! Not that there's anything wrong with that!
I don't have any soft covers myself because they're just not as durable. I treat my Moleskines in a fairly casual and care-free manner so they have to stand up to some punishment There are times where I need something flat/stiff to write on so the softies just won't cut it. My brother uses softcover ones and they are quite classy. I would use them if I took better care of my notebooks.
Actually, the softback Moleskines are remarkably durable. I keep one in my back pocket all the time, so I sit on it, etc., and it's fine. One of the brilliant things about the softbacks is that the second half of each notebook is perforated near the seam. Makes for easy tearing of pages, without the entire thing falling apart.
I think the softback makes more sense, because such pocketbooks are meant for sketches and quick thoughts, not necessarily something you'll make a master flipbook out of. And they'd probably reside in your back pocket; it hurts sitting with something hard there!
The construction of the large moleskine hardcovers is fantastic, it's just too bad about the paper quality.. at least with fountain pen use. I get really weird feathering with just about every ink, at first it looks ok then some sparse different kind of fibers soak up the ink with pretty ugly results.
Staying in the Moleskine line I've found the paper in the Cahier notebooks to be much more suitable to fountain pen ink in another very handy form factor, though not quite as durable as the hardcover.
Besides a cahier in my back pocket (and one in my jacket pocket, and one in my bag...just in case), I also have a hardback large notebook, which can be conveniently carried around if you're in the habit of carrying a bag. It's a good idea anyway, carrying a bag around. Be prepared, etc. I have extra headphones, headphone splitter, ear plugs, pills, etc. with me all the time. Both soft and hardback Moleskines are great, for different purposes. Gosh, I sound like a salesperson.
I have several shapes and sizes, usually graph-paper ruled, and use with several fountain pens from XF nibs to 1.1mm cursive. Find the pages take well to fountain pen and their inks. Maybe I got a great batch, but don't understand the talk of them not taking to fountain pen inks. Mine do and I love 'em.