Drum brakes have more grabbing power- more than discs- but they start to fade immediately because there is nowhere for the heat to go. Thats why they have poor 60-0 stats.
Two things I remember about driving with power drums:
1)they lock up very easy!
2)they can fade to the point of failure very easy, especially in the mountains.

You can compensate for lockup by practicing hard stops a lot, but if you drive a modern car all week, then drive the bird, you can surprise yourself in a panic stop. For fade, you can mitigate it by not letting them get too thin.
I noticed a huge difference when I switched to discs, but it looks like that website offers a very good compromise. I also read somewhere that you can mitigate the heat buildup of drums by drilling quarter-size holes in the face of the drum, to allow them to air cool. I never had the guts to cut up my stock drums tho, they're still sitting on the shelf in case I want to go back to stock.