Thanks for the info.
Any models you'd recommend that would yield a clear improvement? (In the 300-500$ range)
The Canon camcorders with the "HD CMOS PRO" image sensors would be an improvement over the small sensor of the HF20.
For example; HF G10, G20, HF M41.40, 400, HF M50/52/500 all have that sensor. They have a couple of these as refurbished models at the Canon Direct site.
Not sure what you're using it for, but something like a micro four thirds interchangeable lens camera will have much bigger sensors/better image quality than a camcorder,. For example Panasonic GM1, GM5, G6, GX7, GH1, GH2, GH3, GH4. The GM1 is in the $500 range, although a very small camera if that matters to you.
A good camcorder will give you farther, quieter zoom and superior image stabilization and likely better audio options, depending on the model. Camcorders tend to look like video, similar to TV/not like movies.
The bigger sensor micro four thirds will yield better low light/image quality and shallower depth of field/subject in focus with a blurry background, film look. Plus you can buy additional lenses. The camcorder lens are fixed/non-removable.