It works well, even without the rubber shoulder. I think some people said they could hear a bit more noise when running, but if you wear earplugs, it's not likely to be a concern.
The lower rpms (~7%) make a nice difference on higher speed runs, where it seems a lot more relaxed compared to what it was with the original gearing. I think the issues with the speedometer changes have been discussed before, but just in case someone reading this hasn't read the other threads - the speedometer reading does not change, what changes is the accuracy. You typically had a 8-9% error before, the speedometer will now be only 1-2% off the real speed. This means that you will still see 80 (or 82 to be precise) at 6K rpm, but before you were actually traveling at 75 MPH at 6K, now your real speed is 82, as indicated by the speedometer.