I bought some imitation Moleskines from eBay about two years ago. Mistake. They "looked" the same, but they were rather flimsy, and not so well constructed. Also, not as durable.

There's something about Moleskine notebooks (or other similar "expensive" notebooks) that needs pointing out: The cost itself is a positive. I'm less likely to lose/misplace a $10 notebook than a flimsly 99 cent one. I use mine as a semi-wallet, w/ receipts and extra cash, and such inside the pocket. And then use it take notes as I run around the library doing my grad research (the pocket also carries my library copy card). The great thing is that sometimes I just pop in the library, w/o my laptop or other materials, but I have my notes (articles to look up, etc) and my copy card, and I'm ready to do some impromptu research work.

My guess is that those who mock people who use expensive notebooks (whether it's Moleskines or not) don't do a lot of journal/personal writing, or don't value writing as a creative excercise on a regular basis or as an integral part of their daily life. But I could be wrong.