What he posted isnt just jailbreaking. Most of that was installing a ROM. The Rooting is just the first thing you do and it was just installing a Zip file and flashing it... though ive installed ROMs that rooted the phone for you so you didnt need to root it first.
Its only complicated if you cant follow directions. Not saying you cant, but some people just dont want to read anything.
I dont see a quick guide.
The advantage to rooting separately is that you can uninstall bloatware and install software such as Google Now while leaving the stock rom and radios in place. As I mentioned, follow the rooting procedure to the point of flashing the upgraded ClockworkMod Recovery via Rom Manager. Then download the zip file, which contains the files for Google Now. Save that to your phone and install. Obviously, you install it via ClockworkMod Recovery. Really quite simple.
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One thing that gets people is that the phone will overwrite ClockWorkMod Recovery and revert back to the factory Android Recovery. You cannot install unsigned rom's or software with the factory Android Recovery. So, make sure you are using the right recovery. This will be obvious when you boot into recovery mode. It will say at the top either Android Recovery or Clockwork... I hope this is not too confusing... lol
Also, you need to do a factory wipe via ClockWorkMod before installing the rom. (not so if you are just rooting) That way you have a clean install. Flashing a rom without wiping is called a dirty flash and can lead to old code being left behind and conflicts.