Note: I try only to remark upon limited time and/or rare products on this blog, not simply new products. Unless otherwise confirmed via research, any product presented on this site is presumed to be limited time and/or rare by my own personal opinion. This product is an example.
I would say that this stuff is mostly disappointing. A trend I've come across is that when processed food is flavored with "dulce de leche", it will most often simply contain both sugar and some sort of butter flavoring in an attempt to capture the milky flavor of dulce de leche. (This product may suffer from an identity crisis, since the product's front packaging indicate, at different spots, that it's both flavored with dulce de leche and caramel, which are not the same thing.)
That may be an oversimplification in this case, but the flavor of these Cheerios are not completely unlike the Honey Nut variety. Half of the cheerios in this box are made of corn (as opposed to the normal wheat), which I imagine is thought to add to the caramel-like flavor via the corn's natural sweetness, but instead it lends the flavor of a simple corn cereal, like Corn Pops.
In the end, while this cereal isn't bad, it simply tastes like sweet Cheerios with additional flavors of corn, butter, and perhaps brown sugar.
Dulce de Leche Cheerios: (Good)