Most of the reviews near mine appear to be from people who have not used this book in several sessions or read it thoroughly. I want to give the book 1 star simply to cancel out the 5 stars given blindly by the WotC fanboys (of which I would be one if they weren't so lazy) but 2 is more accurate.
Yes, the Spell Compendium has lots of material. Lots of unedited material. There are numerous mistakes throughout the book. I do not mean spelling and grammar (although there is a lack of that at times) -- I am referring to using proper game terminology, references, matching description/header, and so forth. Some spells do not match up with their core counterparts--some underpowered, some overpowered.
There is a two-spell combination that grants True Resurrection on a party member at 9th level Cleric, (IIRC but it might be 7th). At no XP or gold cost. That is Character Level 9, not spell level 9. I won't list it here because it's ridiculous and bad enough already, but it's not hard to figure out if you read the cleric lists.
Try to find "Draconic Polymorph"...you won't.
At least one of the spells (Graymantle) makes reference to an inapplicable 3.0 mechanic (Regeneration).
A lot of spells give different schools in the lists and in the description. The teleport spells are listed as Transmutation spells, which was changed to Conjuration in 3.5.
Some of the spells listed do not have any data for duration, range, etc.
Yes, this could be erratad, but
A) There is just _so much_ to errata. I don't want to carry around a handbook to go with my manual.
B) What exactly are the editors getting paid for? To make a physically attractive and appealing book, I guess.
C) WotC needs to PLAYTEST their material. Externally. They are the richest game company in the world, but apparently also the laziest (essentially TSR except with marketing execs and MBA's). It costs nothing to test externally except some very fine print credits on half of one page, or in the absolute worst case scenario, some free product.
In my opinion, it was lazy of WotC to create so many classes and not provide updated spell lists for any of them (especially base classes--PRC's I can understand). Instead it gives "suggestions" which is of no help to a player who bought this book but whose DM won't let him use anything out of it due to the spell not being on the player's spell list. Any good DM could write up hundreds of spells on a dozen spell lists over the course of several weeks of careful research...or he could be writing and running adventures. Why pay $40 for a book that expects you to do that work? Their supposed excuse is that they would have had to drop some spells to include new lists. What is the difference if you can't use any of the spells in your game, anyway...BECAUSE YOU CAN'T PROVE THE SPELL IS ON YOUR LIST?
I also say that if you are going to ask the DM to do that much work, why not just ask him to write 1,000 new spells? They would be at least as balanced and thorough as the book we are paying for.
I am not saying all of this in a pout because my DM won't let me use the book. All of my DM's will, but **I wish they wouldn't** because there needs to be an explicit spell list for each class, not just ad hoc spell casting out of a book no one else at the table is familiar with. I also DM and use the book only with much scrutiny.
There was a small but good thread on this at the publisher's (WotC) site, called "Spell Compendium Errors/Querries." Others may be found with a minimum of searching.
Only buy the book if, like me, you are a sucker for having every POS book put out by WotC on your mantle to impress your friends when they visit. Or if you make way more money than you need and have nothing else to spend it on; personally, I would rather have more minis.
If you do buy the book, expect to use it to pick up a couple of spells per caster PC to fill a gap in your (previously balanced) spell list or because you can't pass up an overpowered spell.
For the most part, expect it to collect dust (outside of those 2 uses per PC) and be a source of regret, unless you fall into one of the above 2 categories (rich or stupid).