I have the Mattel set, which I also quickly bought upon announcement of Kirsten's archival. The top is a white flannel fabric that I feel rather ambivalent about - I like the cut of it with the sweet little keyhole front, but the fabric attracts lint from her woolens like a magnet!
The skirt, however, is lovely - a thick wool felt that holds a hooplike shape with an embroidered waistband and bias binding trim. It's really festive for the holidays - although I also have Kirsten's Santa Lucia gown, I prefer to have her in this ensemble with her "woolens" during the holiday season. The ribbons are also very pretty! They coordinate well with the skirt.
This set is fun to play with, since you can mix and match it with a variety of socks, shoes, ribbons, and other accessories. I probably spend more play time with Kirsten's winter clothes than any other.
The picture isn't the best reference of the top due to her woolens being included in this shot, but it shows off the skirt beautifully.