I've been doing mat work for several years & feel it's an important part of my fitness routine. Both for core strength & flexibility. It's much tougher than it looks, & like yoga, you get out of it what you put into it.
If you've seen the Winsor infomercial & you liked her personality, go for it. There are lots of good basic pilates videos, you just have to chose one that fits your personality. I think Stott's instruction is terrific but many find her too dry. Voight's videos are more pilates inspired than classic pilates, but they're fast moving & she's perky. I think she neglects fundamentals, but you'll still get a good core workout.
If you can, attend some mat classes after doing a video a few times. The movements are so small & often internal, that it's really difficult to perfect your form without a live, experienced instructor.
Debra