I looked at label makers a couple of years ago and was dismayed by the lack of solid facts. Most reviews said either, "makes great labels" or "labels fell off after x months."
I looked more carefully at the industrial lines from Brother and Dymo. I was interested in a variety of sizes, adhesives, wire ID and heat shrink tubing capability. Information was so poor, I ended up buying a Dymo Rhino 4200 for home, and a Brother PTE500 at work, and learned a lot.
First, the industrial labelers can use both the industrial label tapes, which have several adhesives and styles, and many of the cheaper, more common removable office tapes, which are not called, "permanent." Many home and office label makers can't use the industrial tapes. You can decide how important the industrial tape offerings and permanence are.
2nd, the major difference between Dymo and Brother is that Dymo heat-prints on top of the tape and Brother prints under a clear top. Thus, Brother is much better at wear resistance, but it has to spit out a bit of blank tape before every print, to ensure the tape sandwich is together. People hate this, and it seems wasteful. Dymos don't have this problem. The standard Dymo tapes are vinyl and seem to ooze a bit of adhesive out the sides, which the Brothers don't do.
3rd, do you want a handheld unit, or a larger one that can hook to your computer? Some of the expensive hand units also hook to computers. I ended up with handhelds, but computerized units seem to offer more print flexibility.
I did not look into other industrial units like Brady, nor did I look at home/office labelers that could not use the tapes I was interested in. Generally, the very low cost units cannot use the nice industrial tapes. Oh yes, the cost of the tapes will annoy you, but they are great for us OCD types.