I've read Vol. 1 but didn't finish Vol.2 yet (stopped a couple of months ago because I got a bit lazy).
In Vol.1 he talks about simple concepts but I realised that they were very solid and it shows there was much thought put into making it easy to understand. In fact most of what BalugaWhale explains there one could say "Yeah I knew that". But many if things, although thinking that you know you aren't fully aware. What he does is rationalizing some things players do unconsciously. For instance the reasons why to bet and the reasons when to check on showdown theory are some of the most simple but yet extremely solid fundamentals in thinking poker.
I thought it was a very good read mainly for micro-small stakes players.
Vol.2 isn't that much groundbreaking as well but it's more advanced. He explains things very clearly like a coaching session. And after each chapter you feel a good understanding of his ideas. He's topics include advanced showdown theory, deepstack play, dead money (again), squeezing, playing vs shortstackers (not very useful to me since I avoid them like hell ♦), etc.
It was very informative but I like that it makes you think more about things that I wasn't aware or conscient about.
Is it worth the price? Well most of these new school poker books are very expensive and although many of them are very good I don't think in general they are worth the price. Mainly because I play microstakes. But one thing I can tell you, these 2 books are better for micro-small stakes and I found them more helpful where I stand than "Let there be range" or Bobbofitos bible.