I agree with you.  I have had my MSD installed for about 6yrs now and have had no problems with it.  Then again, I mounted it inside the cabin and out of the elements, and I do not do silly things like remove the battery cable when it is running  I think the biggest thing that kills MSD boxes, and any black box for that matter, is a combination of heat, moisture, and vibration.  If you mount the box in the engine bay, you are asking for trouble.  Also you must use a suppresion wire...not the wires that MSD sells, but a tru EMI suppresion wire like Magnecor, even OEM style NGK work better at EMI supression than some other brands.  Just my .02...maybe I have been lucky or maybe I found the secret...I do not know, just know it works for me.