I had a terrible experience with Veritas. They say you will get 15 prep tests, however it is only 5 and of those 5, only 3 are worth anything. My veritas prep instructor himself told me this and my experience backed it up.
The books are very low quality, filled with copied content (or so it seemed to me) and the whole concept that you can throw money at something and make it work just seems crazy. My roommate had a crappy experience with Kaplan and I know nothing about Princeton. Sorry to be so gloomy, but whatever.