In addition to the reviews for the individual releases, I also wanted to add my thoughts on the series (Easy Pilates, Cardio Pilates, Pilates for Abs and Energy Boost Pilates).
These are compact, tight workouts (30 minutes or under). While I do own longer Pilates workouts, I don't reach for them nearly as often as I do the shorter releases. Also, I love that no equipment other than a mat is required.
There are two ways to get these workouts. One, you can buy them from the Gaiam.com website for $25 plus shipping and handling. You have the option of either two DVDs or 4 individual VHS. Two, you can buy these individually, on DVD (and VHS for some), through Amazon.com, Borders or other movie outlets.
All things being equal (e.g., shipping costs), I recommend buying through Gaiam.com since the individual releases are going for between $10 and $15. While $15 may not be excessive for a 30-minute workout, in my opinion, $10 for 15-minutes is. The caveats are: 1) if you have the Beginner and Intermediate Gaiam DVDs, you already have the Energy Boost workout; 2) Pilates for Abs was previously bundled with Pilates for the Lower Body and is now also bundled on the same DVD with Balance Ball and Yoga workouts from Gaiam that target the abdominals; and 3) unfortunately, you have to buy all four releases from Gaiam to get the discounted price- you can't just buy one DVD. Still, even if you already have the Abs and Energy Boost workouts, it might still be cheaper to buy the whole set and either exchange the Abs/Energy Boost DVD on the VF Exchange or sell it through the Ya-Ya's Swap (I purchased mine through the Swap for $14- thanks Michele!).
They are nifty little workouts, each with their own twist. If you like Ana Caban's previous releases, these are recommended.
Please see comments above.