Stay away from adhesive labels for DVD's. Unless you can get permanent adhesive labels which are not very accessible to the public. Plus the public is very unaware of the difference in adhesive labels. I am in the printing industry for many years and have seen people make the wrong choice nearly every time.
Hence the peeling off of labels. Most adhesive label stock available to the public market is either non-permanent or semi-permanent. This is so people can easily peel a label back up if they make a mistake in placement. With permanent adhesive stock this is virtually impossible to do.
I have a Canon Pro-100 and Pro-1 printers with printing trays for CD's & DVD's and would recommend that all the way. Printable CD's & DVD's are available and print very nice. Never have to worry about labels peeling off, as has been stated here quite a bit, or unbalancing the DVD.