When looking for some sticky tack to put that poster up on the wall without using push-pins, one usually looks for the Scotch brand. After all, they do know how to make things sticky. But one may also find Simply Tacky a (terribly named) product that does the same thing. Is it worth it to search for the right brand?
To start off with, both items come with very close to the same amount of product. The Scotch packaging is slightly smaller, and more packed with use information and diagrams. Both are cut into four similarly-sized bars. The Scotch is the only one with a weight limit (of 1lb). Both are quite white, and are easy to pull apart and shape to stick onto a surface. Both are very grippy, with the simply tacky being a little more malleable and aggressive. It breaks into pieces more easily, though.
As for what they can hold I’d say it’s about equal. The Scotch says it’s up to a pound, but they don’t tell you how much product to use. With a tiny, equally-sized bit of each product (weighing less than a gram) I was able to hold 70 grams (2.4 oz) easily, and I’ve held up to half a pound products stably up with enough (It will do up to a pound, but only in certain configurations of putty and object). Putting that same small piece of product up with a 7oz (198g) item, both failed fairly quickly with the Scotch maybe a little faster, but I’d chalk that up to my tests being not completely scientific.
Overall, I’d say both products are really the same on the user’s end. Their uses are the same, price can be more or less in favor of each brand depending on where one shops, and they hold almost equally well. If you’ve got a choice in the aisle, then I’d say take the cheaper one, but it’s not worth another trip to get the right brand.