I think that it's worth it to get both books if you can afford it. They cost the same price and the campaign setting has almost as many spells as the codex (with no overlap). If you don't get the setting book you are missing some important basic spells like dispel magic, sense magic (along with the new rules needed for spellcraft), detoxify poison, a couple of mid range healing spells, a spell for creating skeletons, a bunch of scrying and telepathy spells, and others. You could just get the codex but I think that there would be a few small holes to be patched (or ignored).
On the flip side of the coin, only the codex has rules for magic item creation and for determining the Casting Threshold for new spells that you invent.
In addition, with the campaign setting book you get other classes like mounted warrior, noble, stalker, etc. I am of the opinion that if you change the magic system you will need these other classes, or something like them. Changing the magic system in D&D requires that you modify or remove all of the following: cleric, sorcerer, wizard, paladin, ranger, druid, and bard. In addition, if you change the scaling of magic item power as people increase in level, monks become unbalanced as well. With the majority of the PHB classes needing to be removed or reworked I think that it's really just easier to get the book and have the work already done for you.
The setting book is pretty rules heavy. I actually think that it's pretty lacking in info about the world itself. This is a weakness for people who want to play in Loerem, but a strength for people like me who primarily want to pillage the book for the new rules.
It is a bit pricey to get both perhaps, and there is overlap, so I'm sure you could get by with just the Codex, but there is definitely still value in the campaign setting book if you can afford them both.
As before, someone please correct me if I've gotten anything wrong. I'm still going over the books, but so far the more I read, the more I like it.
On the flip side of the coin, only the codex has rules for magic item creation and for determining the Casting Threshold for new spells that you invent.
In addition, with the campaign setting book you get other classes like mounted warrior, noble, stalker, etc. I am of the opinion that if you change the magic system you will need these other classes, or something like them. Changing the magic system in D&D requires that you modify or remove all of the following: cleric, sorcerer, wizard, paladin, ranger, druid, and bard. In addition, if you change the scaling of magic item power as people increase in level, monks become unbalanced as well. With the majority of the PHB classes needing to be removed or reworked I think that it's really just easier to get the book and have the work already done for you.
The setting book is pretty rules heavy. I actually think that it's pretty lacking in info about the world itself. This is a weakness for people who want to play in Loerem, but a strength for people like me who primarily want to pillage the book for the new rules.
It is a bit pricey to get both perhaps, and there is overlap, so I'm sure you could get by with just the Codex, but there is definitely still value in the campaign setting book if you can afford them both.
As before, someone please correct me if I've gotten anything wrong. I'm still going over the books, but so far the more I read, the more I like it.