I have been doing Karen Voight's Energy Sprint. I first bought it a long time ago due to its placement in videofitness.com's favorites section. When I received it, I did it once, and did not like it. It has been collecting dust until I pulled it out a week or two ago and have started using it twice per week. It is mostly low impact, and great during the second trimester, perhaps the third as well, however, I am not there yet. For me as an advanced exerciser in my non-pregnant state, it was hard to put away a lot of my fun high impact workouts. But I have, and I am glad I never traded Energy Sprint because it seems to be perfect for me at 22 weeks. I wish I had more like it. It is the only Karen Voight workout I own. I may try some of her other cardio workouts to see if she has more good low impact. Also, it surprised me how well it got my heart rate up, considering when I did it a long time ago, it seemed way too easy.
For weight work, I continue to use mostly Muscle Endurance and Power Hour. I just do push ups instead of the laying on the back chest exercises.
emily