FWIW, if you have a portable recorder like the h1 or h4n, you should be able to use the built in mics and also record straight into the camera via a short cable. With the H4n, you could use external microphones and have the same function as the juicedlink (although not the same quality). And you still have a portable recorder for audio only. You can also use it as an audio interface to your computer via USB.
Having said that, I have a H4n and I just sync in post. I tried it into my camcorder and was more frustrated by all the cables than I was having to sync later. I have used it as an audio interface and it is just OK for that.
If I were looking today, I'd get the H6. The H4n has a little bit of a hiss that I find annoying, and the interface is not particularly elegant. Plus if you're careful, you can do a lot with 6 channels of audio that will allow you to actually mix instruments in post. I'm not rushing out to upgrade, and the H4n is good enough for what I do, but it's a bit dated now.