I have the full set fitted - fast road.
They definitely increase the noise and vibrations to the cabin, but not enough to make it too intrusive. I still cruised 1,000 miles to LeMans and back in comfort.
For me, the cost was OK, as I was getting through standard mounts at an alarming rate, especially the rear mount.
No problems with fitting - they are a straight replacement
If you're running a standard car exclusively on the road (i.e. No track days), then I would recommend new standard mounts over Vibra Technics