I use a brother p-touch for all my of my labeling needs and I can tell you this. Once they have been in place for about a month, they do not like to come off. I got over zealous labeling a rack that I had a bunch of switches and patch panels in that was made of aluminum. Later decided to change some things and I had a bear of a time getting them to peel off.
And if you do like Larry and use the clear tape it will almost look like your panel was printed that way.