I've heard that the phb is saddle stiched but, honestly, beyond that I don't have the knowledge to back it up. One of the playtesters passed this information around (not the Trolls, so if it's not accurate don't give them grief) and it's a source I trust which is the best I can do really. Well, other than tell you, no matter how the book is bound, it's done very well and is more durable than most books you see on the market today. So, either way, it's a bargain at $20.
The encumbrance system gives each character an enecumbrance value based on strength (8 + str modifier) and each item an encumbrance number. This number takes into account weight as well as how large something is, etc. So while you are told how much weight your character can carry or lift the weight of an item doesn't determine encumbrance (so no more str 18 warriors walking around with a chest of gold, two sets of armor, and a dozen weapons all without any penalty). Wearable items have a reduced encumbrance when they are actually being worn and items made to carry other items reduce the total encumbrance they are carrying.
For example, cloth gloves are enc 1 but if you are wearing them they are reduced to enc 0. And a small pouch can hold 1 enc worth of material but as it reduces the enc total it carries by 1 anything you put into a small pouch (rogue's tools or holy symbol for example) becomes enc 0.
It's simple, fast, generates low numbers that are easier to keep track of, and it works better than just basing what you can carry on weight. Now I will note that it still requires the use of common sense by the CK but to a much smaller degree than any other system I've ever encountered.
