I got the 75 durometer (red) mount about 2 months ago. My car is a 2011 GTI...This mount definitely keeps the engine movement in check while still allowing it to flex just a little bit. The mount makes shift engagements incredibly precise. The mount also helps you feel an appropriate amount of feedback through the clutch pedal. I can finally shift with 100%confidence, no matter what the driving scenario.
There is a small amount of vibration at idle. At first my radar detector vibrated a lot (blendmount on the rear view mirror) but some foam shims took care of that. Now nothing in the cabin vibrates or rattles, but the entire car resonates like a true performance car. It definitely takes away some of the civilized feeling of the car. I believe that most people on this board are enthusiasts and will appreciate the "raw" feeling that this mount gives the car. The change is not drastic though. My wife says the car is still comfortable. She doesn't mind the slight noise/vibration at idle because her head doesn't whip forward on shifts any more. I also feel like I am driving better now because the car will give you lots of feedback if your RPMs are too low. The car vibrates a little more with the A/C on, which may become a problem in the Mississippi summer. We'll see about that soon enough.
One note: Do some research on the installation before you begin. There weren't any instructions from HPA in the box. The instructions on the HPA website make the installation look easy, but removing the stock mount is pretty difficult. The stock mount took me about an hour (and lots of cursing) to remove. Also, one of the more extensive DIY guides I found on vwvortex had the wrong torque specs. It looks like the writer of that DIY accidentally doubled the torque spec when he converted from nm to lb/ft. I used his torque setting at first and my car vibrated like crazy for a couple of days before I realized what happened. I re-torqued the bolt with the proper spec and it has been very comfortable ever since.
I can certainly see why VW designed the stock mount the way they did. I'm sure that most consumers prefer the soft, refined feel that the stock mount gives the car. I admit, it was one of the things that I really liked about the car when I test drove it. But after living with the car for a while I wanted a more solid mount. This mount really made a significant impact on the way my car drives, especially when you consider the price compared to most mods.