The Zeroll ice cream scoop ($14) has been around for a long time—in fact, it's celebrating its 75th anniversary. It must be doing something right to be essentially unchanged for all that time.
Rather than being a disher-style scoop, this one is a one-piece unit with no moving parts. Well, unless you consider the sloshy stuff in the handle a moving part.
The special feature with the Zeroll scoop is that the liquid in the handle is supposed to transfer the heat from your hand to the scoop, which then makes it easier to scoop hard ice cream. And there is definitely heat transfer going on. Leave the scoop in the ice cream container and you'll have a frosty-cold handle and a puddle of melted ice cream around the scoop.
But how does it work when it's actually scooping ice cream? Here's the deal. If your freezer temperature is set to "surface of Pluto" and your ice cream is tooth-chippingly hard, this scoop is not going to glide through it like a hot knife through butter. But if your ice cream is just reasonably hard, this scoop will make the job a little easier. You still need to put some effort into harder ice creams—it's a scoop, not a magic wand.
Since there aren't any moving parts, this scoop is pretty much indestructible, and the big handle is easy to hang onto. The only downside is that this scoop isn't dishwasher safe. The scoop is aluminum, which doesn't behave well in the dishwasher, and the heat of the dishwasher can make the liquid in the handle expand too much and leak out. But washing it by hand isn't a big deal since it's all smooth surfaces.
An ice cream scoop isn't an earthshaking gadget, but this one's got a lot going for it. Even if you don't find that the heat-transfer feature makes any difference, it makes a nice-shaped ice cream ball and it's sturdy enough to last nearly forever.
Disclaimer: Testing samples were provided to Serious Eats.