Cliff Notes version: If you use your white platform that came with your Big Shot, then use one of its cutting pads, then the Cuttlebug A-2 embossing folder, then the second cutting pad on top (like a sandwich), it works perfectly.
Extra babble beyond the Cliff Notes version: It (CB A-2 embossing folder)doesn't
completely cover an A-2 card front, but you can either layer it on a card base OR you can cheat with the size just a bit so that your card ends up being about 4" x 5-1/8" with a bit of creative trimming and scoring. Does that make sense? *I just tried to upload a picture here, but it is too wide to upload.* Cheating on the card size to make it cover the whole front is explained further
here if that is unclear.
Finally, here's a
direct link to JulieHRR's great writeup about the Big Shot and Cuttlebug comparison. I think that this is the one that Kathy meant. HTH!