this was debated yesterday between me, mike and other members of the support group. I wanted to set it to 99 (maximum value) to make sure we are always overriding the default comments widget (the reason why we are putting this in is when the priority is lower than the default widget given by the theme, both widgets show up), but mike didn't seem to think this was a good idea. So far, I've only dealt with themes that set the priority at 10 explicitly, so setting 11 would work fine. However, I'm not really sure if there's themes out there that might set priority a bit higher; not sure what the best practice on something like this is.