So what is up with the auto-detect? Does it work for you guys? How does it work?
It puts me on High Spec and it runs like shit, is there something wrong with my computer that I have to fix? Or does the Auto-Detect just not work?

As long as I've been a PC gamer, experience tells me that Auto-Detect is always shit in just about every game. Best to customise your own settings and tweak them to your personal preference.

It set my resolution really high and lowered the quality of graphics. I quickly changed this to balance it out. I have no idea what the game was thinking.

It put everything to low on my system, yet I'm playing at 30-35 fps on high...

It did a pretty good job for me, however it had AA and motion blur on.
I would rather play around with the settings to be honest.

I'm using Ultra settings, with Ubersampling, SSAO, and Motion blur OFF at 1920x1080 and the game looks beautiful and runs flawlessly.  
core2quad 2.4ghz + GTX 480.

Well, for pc gamers, the auto detect really means ignore it and max out the game, then back down settings until it's playable.