By coincidence it also offered 3DFX Voodoo 3 boards at a deep discount. I also had an Antec case with 250-watt power supply. The AMD Web page showed that it doesn't recommend that power supply for the K7 Athlon 700 MHz chip. Athlon chips are famous for using a lot of current. Fortunately, I had a PC Power and Cooling 350-watt power supply, and it only took a few minutes to remove the Antec supply and install the PC Cool.
Antec cases use little clips to fasten the motherboard to the base plate.
I don't like those as well as the brass hex posts PC Cool uses. I tend to drop them, and they'd fall into cracks. The one thing you don't want to do when you're building a machine is to have small loose metal parts in it. They're sure to short something out. Once installed the little clips seem more than adequate.