[JollyElm]

To me it's pretty simple. The 71's are more popular for a few reasons:

1. The tough black borders make most people like me on the constant lookout to upgrade the cards we have.

2. There's a very wide variety of action shots that add a great visual element to the set.

3. Since the set was released in series, it's always tough finding the much sought after high numbers. By 1975, that element was gone.

4. A bunch of HOF'ers--Mays, Banks, Wilhelm and Mazeroski immediately come to mind--had one of their last cards in this set.

I think the 1975 set unquestionably wins the HOF rookie card battle, though. Brett, Yount, Rice and Carter. Niiiiice!!