I'm a fan of Too Many Spells, so I jumped right over and bought it. I've got the various kindred spell books that Ken has released as well.
The introduction describes the spells as ones that got edited out of DT&T, or changed in DT&T. Many of the spells are represented in DT&T, but at different levels, costs, effects, etc.
There are 42 spells in the book.
17 do not appear in any form in the DT&T rulebook. (40%)
11 appear in the DT&T book in modified form.
14 appear in the DT&T book in pretty much the same form.
There are a lot of good spells that fill gaps in the DT&T list. DT&T in many ways feels like it should have a spell that does one thing or another at a particular level and with a particular cost and power where it doesn't.
I think you'll find a good selection of those here.
There are some specialty spells in here, particularly ones that are more conducive to role playing than game mechanics. But the spells that really sell me on this book are the ones that are going to get used a lot that fill those gaps in the relatively short DT&T spell list.
There are a lot you'll recognize from 7th edition or 7.5, if you've played those. And ones that were in 5.x but not Deluxe.
Each spell lists the kindred it is associated with. In many cases, it's a spell that is in DT&T, but at a different level and cost for a particular kindred. The new spells likewise have a kindred associated with them. This is good campaign fodder, as a spell that's relatively high level and expensive from the Wizard's Guild might be a lot cheaper and easier to cast IF the character can schmooze it out of a spellcaster of the right kindred.
Many old favorites are back. Like "That's a Natty Beard." It's a signature spell for T&T, it's hard to believe it got left out of the core book.
The spells run from 1st through 4th level. In my opinion, low levels spells are the most valuable because they're the most used. So you won't find a "fixed" Death spell in here like the hardcore 7th edition version of Death Spell #9, but you will find some nice additions for your low level players, either of the listed kindred or "borrowed" from another.
The art consists of 3D renders by Robin Stacey (Greywulf), and line art by a number of artists, spread through the book.