The Sizzler is the one Estes is most interested in keeping alive, because they have the rights to the name, much the Mattel's chagrin. If you remember the Mattel Sizzler race cars, you will know why Estes collected a royalty from Mattel for use of the name. Estes can only keep the rights if there is a current product (within about 3 years, IIRC) using the name, so that is what they do. It doesn't matter what the design looks like, it just matters that the name is used.

Matt