The best part of the DMM Peenut is its slightly offset taper, which allows them to fit into pin scars where another climbing nut might not be fall-worthy. They are better than WC Superlight Rocks and not quite as good as DMM Alloy Offsets in these types of cracks. The Peenuts offer one of the best aluminum options for thin crack protection. Aid climbers will enjoy Peenuts because of their pin scar prowess. While they didn't fit into scars quite as well as DMM Brass Offsets, Peenuts were more durable. Although Peenuts are not a complete set on their own, their color coding matches the rest of the DMM and Wild Country nuts, making them a convenient addition. Also, the large amount of surface area gives these nuts greater holding power.
Aluminum doesn't bite as well as brass, bronze or copper. The large surface area on the sides of the nut, while offering more surface, can be harder to place in smaller cracks. These larger sides worked better in smooth rock than in highly textured or irregular rock. Peenuts were also harder to clean than similar aluminum nuts. They were among the poorest nuts for placing in parallel sided cracks.
Peenuts are a good complement to a rack of any type, especially those of other DMM or Wild Country nuts where Peenuts will follow the same color scheme. They are best for smaller cracks if you aren't willing to give up the durability of aluminum. They fit pin scars and shallow flares well for aid climbers but they should not replace a set of brass nuts.
Peenuts are functional and durable. Plus, they are only $55 per set, much less than other specialized micro nuts, whether brass, bronze or aluminum. They should not replace an aid climber's brass nuts but they complement that set quite well.