Knoll's horseradish root is generally thinner and a bit gnarlier looking than you might generally see in the supermarket, but it's certainly not lacking in flavor.
Horseradish root contains highly volatile oils that are released when root cells break down by grating. Vinegar can be added immediately to freshly ground or grated horseradish to stabilize the flavor before it gets too hot, or if you wait three minutes to add the vinegar, you'll end up with a very hot paste. Fresh horseradish can also be finely shaved and used to top a plate of steak, potatoes or anything else that could benefit from a slight kick.
Fresh horseradish should be scrubbed thoroughly before being grated or thrown into a blender, but as a whole root, it can last for many weeks (if not months) in the fridge in a plastic bag.