hi Ctstrphy !
Basically, are all the same: you need a machine suitable for Heavy calculation.
then, you can have 2 big Group of miners
1) ASICS
2) all the Others, mainly GPU/CPU, and HDD
ASIC, is suitable to do just one thing, but very welland fast
All the Others, can be used for mining and other things...
another big big difference between the two groups, is who when you stop mining, ASIC will be used just as door stoppe or if you prefer as paperweight
CPU, GPU, and hdd, can be reused or reselled...