Spark plug cleaning Pros/Cons?

What are the pros and cons of cleaning spark plugs with air/sand spark plug cleaner?

On older engines, it really wasn't an issue. On DI, E-tec or new technology engines, It can produce a round spot on the strike pad, this allows the spark to only hit in one spot on the pad, this wears out the pad sooner. The other problem is that you may not get a good seat on the plug gasket. Once it's compressed, thats it. We index plugs on new engines, sometimes this can pose a problem as it is necessarry to add some torque to get a line up, the next time around, the plug will be loose. http://xs-s.com/zf/images/smile/emthup.gif

Thank you, my engine is definitely old technology being a 1985 gas hog XP150. http://www.bassboatcentral.com/smileys/Laugh.gif
At any rate, there was some scuttlebutt floating around the hotrod circle years ago (when gasoline was less than $.50 cents a gallon) about not using the sand blast plug cleaner because, if you do not remove the residual silica from the plug cleaning process the excess left in the spark plug, would/could do some engine damage.
I was just wondering what the outboard gang thought about the sandblasting spark plug cleaners.

Regards.