Pros: easily adjustable, cuts well for the price
Cons: wire breaks eventually, there is a small hump in the very center or the cake after leveled
I used these for years, and still have a couple. I bought about 5 over the years, mostly because they are so insubstantial, I would lose them! They work plenty well enough for a hobby, but will not cut through a crust, or a large cake. I got around this by placing the wire up against the cake, and cutting it with a knife, then the wire would cut all the way through. And to cut a large cake, you can use this to score and cut the first few inches all the way around the cake, then use the cuts to guide a long knife the rest of the way through.
I did have one that the wire broke, but I fixed it by replacing the wire with a piece of thin wire, by just measuring, then looping the ends around and twisting with pliers. And I found it worked better without the rubber feet. The rubber would catch, and the wire would skidder through the cake leaving a jagged cut. Pull them off, and you get a good cut.
Now I have a $300 cake leveler, that is 300 times better, but this works great with my fixes if $300 for a leveler isn't in your budget. It is a lot easier to adjust than the expensive one, that's for sure.