We've only ever used Dymo. Right now all of our trucks have the Rhino 5200. We use the 18489 Flexible Nylon Labels. They don't come off. If it's exposed outdoor wiring we print on heatshrink.

Every now and then they will run specials. If you buy so many labels (15-25) you get a free labeler kit. There's actually one running right now.
[Link: cableorganizer.com]