I've been wanting a new address book for the past year or so. There was nothing wrong with my old address book; I just wanted something that would give me more breathing room, so to speak. I like to include extra data with my address entries, such as a person's birthday, a couple's anniversary, notes about companies I do business with, that sort of thing.
Usually I would end up trying to cram this stuff into the margins of my old address book, which got the job done but wasn't very pretty.
I also wanted something that was physically a bit larger. My old one was 3"x6", which was considered "medium" size when I bought it, and certainly it was too big to fit in a pocket, but I don't carry it with me so that's not a problem. I decided I wanted something that would allow me to really stretch out and include all the information I want and need, without having to cram it into the constraints that most address books force you to use for each entry. That's one of the beautiful things about Moleskine address books: there are no constraints. The pages are like the pages of a notebook. An address entry can be as long or as short as you want it to be, and can include as many different types of data as you can throw at it. At the same time, it's superior to using a plain notebook because the pages have alphabet tabs, allowing you to quickly find the section of the alphabet you're looking for.
Even though it's bigger than most address books, it's not "big" per se: it fits very easily in my desk drawer and takes up only slightly more space than my old address book.
The construction quality is excellent. The hard cover is very sturdy; the paper is just the right weight (and is a pleasant cream color that's easy on the eyes); it has a built-in bookmark; and there is a stretchy band of fabric that you can use to keep the book securely closed when not in use (which is great for me because I like to use my address book to store stamps, stickers, and address labels -- they would always fall out of my old address book).
There's not much to say about the appearance of the book except to call it "classic." It's a plain, black book. Period. That's it. It's beautiful because of how utterly simple it is.