I’m not wholly convinced the CB makes the KA practice tests. They diverge too dramatically from the four official released exams (for instance, the released exams do not have analogy questions or except questions in the reading section, but the KA material does…). I expect CB outsourced these tests.
It’s been eight years now, but D used Compass Prep – which may or may not be in your area. What sold us was their willingness to tailor the prep to what she needed: not much for the verbal & essay except for a few tips; a lot of work on math. Definitely worth it.
She worked for Ivy Insiders the summer after her first year. It was bought by Revolution Prep, and I’m not sure if they even exist anymore as a distinct entity within that company. I thought the approach they took was very interesting in terms of test-taking strategies, and all of her private students made great gains. The ones who just took the class – not so much, although the improvement was enough that they had not wasted their time or money.