I used to order Cathe's DVDs from Ebay too...until I got one that was for sure a fake and it didn't play in any of my DVD players (and it was the CTX DVD set, I paid $60 for it on Ebay). When I approached the seller to replace it, they weren't listed on Ebay anymore. When I contacted Ebay about the seller, they told me that the seller was under investigation and had been removed from Ebay. That was about 3 years ago and I never heard anything from Ebay or the seller after numerous requests for a refund or at least an explanation. I ended up buying the set from Cathe.com for the full price and of course, no problems! I had to throw the useless $60 DVD set in the trash.
Since then, I ONLY order my Cathe DVDs from Cathe.com to be sure that I get the best. And I do--because if something is wrong with the DVD, I can contact the customer service department to work towards a resolution. I'm sure you know that the last series (B&G, BM2, LIC, DM and CF) was completely replaced due to problems with the DVDs-a feat that I'm sure caused Cathe many headaches, but she got it done regardless. She's awesome like that! In fact, I've already preordered the 4 Day Split because I know that if there are any problems, she'll do whatever it takes to make it right.
I know Collage Video also has Cathe DVDs, but I've never ordered anything from them. They appear to be a reputable outlet for many workout DVDs and videos. My aunt orders her Cathe DVDs from them and has not had any problems. I'm not sure how their prices compare to Cathe.com
If you're trying to save a buck by buying Cathe DVDs from Ebay, I don't think its worth whatever amount you're saving because you never know what you are going to get. Besides, I think the comfort and assurance you get ordering directly from Cathe.com is definitely worth the money spent.
Just my experience and thoughts on the matter...