I'd better open with an apology for starting yet another thread about sharpening and NR but I am still trying to find the best workflow for me (or is that a never ending journey? ).
Once I have made my exposure adjustments in ACR I open the file into Photoshop Elements 9 but ACR has (default) values set for sharpening and NR that I assume get applied during the transfer to PSE. Should I leave these as they are or would it be better to bring the sliders down to zero and carry out these tasks in PSE?
Once in PSE I usually select out the bird (and perch etc) onto a separate layer, apply a heavy NR to the background to create a smooth and pleasing bokeh and then using the high pass filter on the combined image to sharpen. If necessary I might run a gentle NR on the subject but I often find this can cause more problems than just living with a little noise.
I don't feel my final results look as clean and sharp as they do to begin with when incresing the sharpening slider in either Canon DPP or ACR but maybe that has something to do with viewing the raw file. What "format" am I actually viewing while the image is in PSE, is it TIF or an Adobe internal format?
In my opinion, there is no magic way where one way of processing images in this regard is significantly better than another. Best results are probably also dependent on image content, but one can spend days experimenting to see which works better in any one situation. But the next image could be completely different in the workflow to achieve top results. But in practice, what is top versus second or third is very small. Only you can decide if it is worth the effort.
Personally, I use the default ACR settings for sharpening and noise reduction and concentrate on exposure, and lens aberration corrections, then work on the image in an editor on 16-bit images post raw conversion.