I used Sharpen AI on this file and was shocked at the sharpness improvement. This is the Stabilize mode. Image is a screen shot at 100% from the Lightroom Comparison screen. Lens was 40-150 2.8 with MC14 at 63mm, a lens that is no slouch in the sharpness department. F6.3 at 1/320 with stabilization so camera movement should have little effect on sharpness. From the car with arms supported so that should further help the sharpness.
I don't know if the web presentation will kill the comparison, but sitting at my screen in LR the difference popped out at me.
The new four view feature really helps in getting the best result. You have four views in a quadrant: original, sharpened, stabilize, and focus. Select and area for examination then update each of the three modes. You can select the one that you think gives the best results. I thought I knew which mode would be best but I have been surprised when another one is better. So my advice is to check all modes. In some tricky situations I check different areas of the image for comparison.
One gotcha is that the preview seems to show the image with enhanced grain, more than the original. This is misleading because when the file is processed and back in LR, the grain is actually less than the original. My advice is to process disregarding the grain in the preview and to check it in LR. In most cases the grain will be less but in some few cases it may be increased slightly.
There is always the chance of artifacts from too aggressive sharpening. I almost always use the Auto option and have not run into this. The focus mode seems to generate the most artifacts especially when it is the wrong mode for the image. In a couple of cases where I thought artifacts would be a problem, in the processed version at 100%, the artifacts were minimal and did not show at normal magnifications. In any case the resulting processed image was better than the original.