The leather is rather good quality leather. It is not very thick, but it is very durable and could probably endure a fair amount of abuse. The leather doesn't get scratch marks like some other leathers, which provides for a more 'perfect' journal, but also subtracts from the character.
The paper within the journal is thicker than your standard copy paper, but other than that, it is normal. It is not "acid-free," parchment, or recycled but rater just plain (and thick) yellow paper.
The journal is small, measuring in as 4" x 6", but that makes for a good, personal touch. The journal can also be ordered in black, or can be ordered as a 6" x 8.5".
Overall, I would recommend this journal. It's inexpensive price (around $9) is extremely reasonable for the quality you get. However, if you would prefer to go all-out and spend a ton of money on a leather journal, I would recommend getting a refillable pull-up leather journal (8 1/2 x 11) with a basic screwpost. Col. Littleton make a journal that fits in the middle of these two, and it is refillable. The refills can be ordered blank, lined, or for golfing or fishing.