Contrary to what Gatz said, some reviews claim the DVDs to be the best for advanced players. I will however say that if you play above the upper echelon of league players, than the DVDs may not be for you. Well, unless you want a good reference guide to review.
Then again, if you already play at a high level, than you need practice, not educational material. If that's the case, maybe consider buying some DVDs on advanced drills and such. I doubt you'll find any truly advanced material on the market, although I am currently working on a 4th Expert level volume of the Mika series. It wont be released for another 8-12 months though.
Great video quality and reference material. I agree not too much advanced stuff but glad to hear there will be another DVD coming out in the future. Thanks Nathan!