You won't need the Juicelink with the 60D if you are recording to an external audio recorder.
What you will need is a padded mini jack to mini jack cable to take a line out of the recorder into the camera, which requires a mic level audio input.
The main purpose of the Juicelink or Beachtek units is to disable the audio auto gain only feature of the original Canon HDSLR cameras. (and still the only option in the 7D). The 60D has a manual levels option so this is not an issue. This will give you reasonable audio with consistent levels on the camera files, that if you wish can be re-synced with the higher quality audio from the Zoom H4, Tascam or Marantz recorder. One of the reasons the Zoom H4 is so popular, apart from price, is it is very lightweight making it easy to mount on the camera hot shoe.
To dual record and post sync the most basic way is to put a clapper on each take. This can be a simple chalk slate or an iPhone or iPad app. You can also use PluralEyes or DualEyes from Singular Software in post production that syncs the tracks by analyzing the waveform files.
However the most important part of "excellent" audio is choice of microphone, placement of microphone and the environment's acoustics when recording. Monitor the audio when shooting using a good quality set of headphones.
Cinematographer, Steadicam Operator, Final Cut Pro Post Production.
http://www.steadi-onfilms.com.au/
