So, let's start with designs. While both of these products offer a variety of designs, the Kiss Nail Dress stickers offer both flat and gem designs, while the Sally Hansen strips I've seen are all flat. I personally prefer flat designs more, so this does not bother me, but this is clearly a personal preference. I have tried the gemed Kiss Nail Dress stickers, and the gems do hold up very well, so this is by no means a drawback to either brand for me.
Then, let's talk about the application process. Both brands are very easy to apply - you just find the right size sticker for your nail, smooth it on, and file off the excess. However, they feel very different. The Sally Hansen strips are much flimsier, since they are meant to be more like nail polish. They do not feel awkward on your nails at all, where the Kiss Nail Dress stickers are much more durable, and you can tell that they are stickers rather than nail polish. However, that does not mean you should write the Kiss Nail Dress off. The reason that they are more durable is that you can actually cut them, and use them however you want! You could have a funky french mani, or whatever you can think of! Also, Kiss Nail Dress provides more sizes than Sally Hansen, which means if you wanted, you could even use these as a fun pedicure.
I thought that the Sally Hansen strips were much more comfortable once you got them on, but the Kiss Nail Dress stickers are much easier to take off. Since they're just stickers, you can easily peel them away, while for Sally Hansen, you'll actually need to get your nail polish remover out. They last about the same length of time, so they are really very comparable. It just depends on what you want from your strips. One final item of note, however, is that the Sally Hansen strips can dry out! Be careful when you're using them to put them in an airtight container if you're saving them! The Kiss Nail Dress stickers don't seem to have this problem, but I suspect the difference to be that Kiss Nail Dress stickers are, in fact, stickers.
Have you tried these? Which do you prefer?