I just bought 2 of them and they're okay but not great. I consider them for beginners but I would caution you that she does not do a good job of explaining the breathing technique that is crucial in a good pilates workout. I'm planning to order the Stott pilates workouts next because I've heard they're better when it comes to explaining the breathing technique and demonstrating the different exercises.
I think she demonstrates good form although doesn't always explain it thoroughly. Which could be a problem. I learned techniques throught the Stott tapes so when I did Denise I already knew what form and breathing to use. I do really enjoy Denise's pilates workouts-I think they are well sequenced and I always really feel it the next day.
Beth
I agree with all of the above except the comment on Denise's form. I don't think she demonstrated good form on her roll-ups in her JH Pilates DVD (I don't own any of her others so I can't comment on them). Every Pilates book I ever read (and I own quite a few) states when you begin to roll down you pull your navel in creating a C curve with your lower back then roll down your spine one vertebra at a time.... I just did not see Denise doing that all. She did the exercise quite a few times so I don't believe it was the angle it was filmed at. She appeared to go down pretty much stacked (almost like one unit) barely if at all articulating her spine (at least that is the way it appeared to me).
As for Stott, I really like the Intermediate DVD (and Strong and Streamline)....although, I do find the beginning prompts annoying and Moira a bit on the dry side. She is well worth putting up with for good technique, breathing, balance and form.
I have her Hit the Spot Pilates and I enjoyed it. It has 3 core workouts. Also has one workout each for hips, buns and thighs and also a bonus workout (mostly standing). I thought they were good workouts and I felt doms the next day.