Is anyone else getting a terrible framte rate on the PC even if your computer is totally capable? It's been pissing me off to no end, and is really keeping me from playng the game more.

No, I'm maxed out and I get 40+ FPS.

Maxed out  at 1920x1080 and no issues; not sure framerate exactly but its smooth haven't run fraps in the background to see.

Post your specs, otherwise how the hell are we supposed to know what framerate you should be getting.

VSYNC limits your system to 60. Turning it off will only help you exceed 60.

I'm sure he doesn't mean 60 fps as a "terrible" framerate  (besides, turning off VS enables screen tearing which looks much worse than 60 fps).  
 
If your framerate seems abnormally low it's usually a driver issue. Update to the latest correct driver from your card manufacturer (Nvidia or ATI). 

" VSYNC limits your system to 60. Turning it off will only help you exceed 60. "

Let me clarify: 

I've been getting 20FPS at highest settings, and 20FPS at the lowest settings (literally everything off)
 
Is it just the game's coding? There are a few sections that just get choppy as hell for no reason.

What are your computer's specs?

Video Card: ATI Mobility Radeon HD 4670
Processor: Intel(R) Core(TM)2 Duo CPU  T9550 @ 2.66GHz (2CPUs), ~2.7GHz
Memory: 4GB

PC is capable, have you got anything raping your CPU in the background as Beardyduck said.

Update to the latest, even a beta, driver for your graphics card. Radeon drivers are here.

Looks like it was the drivers. Thanks a bunch guys.

Err, maybe not.
 
It was running a swell 60FPS after the driver update (or somewhere around that FPS) and then randomly dropped to the 25FPS again in the middle of combat. But I had already been in two bigger brawls in similar areas five minutes before.