It has been said many times on the forum that this is a feature that is poorly named and misleading, and should be disabled. If you search on this in forum, you'll probably find more, but here is an example thread with a response from lordsmurf that says it well
http://www.digitalfaq.com/forum/vide...libration.html
Here is another example thread that goes over all the JVC SVHS settings, what they do and whether you should use them, also from lordsmurf
http://www.digitalfaq.com/forum/vide...g-jvc-vcr.html
My experience with the JVC SVHS I used, derived from what I read on this forum, was just about everything was disabled, except for Picture Mode, which has the benefit of removing chroma noise (flecks of ugly incorrect color inside a larger solid color). There is debate amongst some as to which Picture Mode to use, but not as much on disabling most of the other settings. Some people notice too much softening of video even in the Auto/Norm Picture mode, but the only option would be to set it to Edit, which turns off the NR function that you payed a lot for when getting this high end equipment. Not to say you cannot. Some say you can remove much of the chroma noise with something like Camcorder Color Denoiser plugin in
virtualdub. That's up to you to figure out what you prefer. Those that say this are typically those that favor Panasonic over JVC, because it preserves more detail. That is something that one should really decide on their own as well. I started out in JVC for economic reasons, and the concern over Panasonic 1980 stability. However, I've since switched to Panasonic because I observed more detail in some videos was preserved. I was able to afford a properly refurbished Panasonic 1980. However, I also noticed some more basic mid-90s Panasonic VCRs that cost much less also had better image detail (my view, at least), although it came without the NR to remove things like chroma noise. Anyway, off on a tangent.
Hope this helps.