PC by far, They are the dominant machines, they give you extreme customization, even without a custom built tower / desktop.
MACs are just awful in my opinion, They normally cost about 6 times more than a top notch pc which has very nice specs / graphics / fps rates, and is 10 times better than what any apple computer can do.
Amazing custom built pcs range between, $300 to $1000, while dinky Macs range between $1000 to $2000