Black Diamond hasn't exactly entered the market and blown its competition away. The performance is good on face and slab, but they lack the steep climbing ability that the La Sportiva Maverink and Evolv Ashima offer and the fabric upper make it a poor choice for those who do a lot of crack climbing.
Performance Comparison
While the kids Momentum performs okay on the the textured rock, it didn't have the best sensitivity.
Edging
Black Diamond did a great job of making a kid's shoe that can edge well. Assuming the shoe fits well (slightly wider) and is sized right, it shines on small holds due to the slightly stiffer midsole and the Neo Friction outsole. Sure, the La Sportiva Maverink outperforms the Momentum, but at twice the price, that shouldn't come as a surprise.
The kids Momentum did a pretty good job at edging in most cases, having more stiffness in the mid-sole than the others we tested.
Crack Climbing
This shoe can work well for crack climbing, having the stiffest sole of the group tested, a nice wide toe box, and the fabric does a decent job of padding the foot, but there is a caveat. The knit uppers can't quite take being stuffed in cracks over and over without getting a little fuzzy, but the occasional crack won't pose a major problem.
A random crack every now and then won't pose much of a problem but the fabric may not hold up well to repeated crack climbing.
Pockets
Although this shoe is wider than most of the others tested, the toes narrow in such a way that it ends up being a relatively pointy shoe. That, combined with a stiffer sole, makes this a good choice for those vertical routes where you are on your toes, but the flat last holds back the performance when the pockets get steep.
The toe shape on the Black Diamond is pretty tapered, considering the extra shoe width, and does a decent job of getting into pockets.
Sensitivity
This shoe has a fairly stiff 4.3mm sole that doesn't allow much for much feeling on the smaller holds, especially for the smaller lighter climbers. If sensitivity is something that is important, the Editors' Choice Evolv Venga has a similar shape and style but a much softer, more sensitive sole. If you're looking for a good sensitive shoe for the steeps, the La Sportiva Maverink is a great option with its No Edge technology.
Comfort
The knit uppers, microfiber footbed, wide toe box and flat last make this shoe super comfortable. We heard some reports that the knit could rub the bare foot, but we didn't have those problems. The breathable knit keeps feet dry, and the comfortable flat last is great for long sessions on the rock. Although the shoe is the widest in the lot, it isn't the highest volume. The top of the forefoot is quite low profile, and the knit fits snug and feels great, almost sock-like. We recommend sizing up one full size for a good fit.
Best Applications
This shoe is best used as an all-around gym shoe and also works really well as a moderate outdoor cragging shoe.
Testing session at Pilot Mountain, NC.
Value
While it is true that it's the most expensive of the flat lasted kids climbing shoes at $60, it maintains a decent value if edging and or gym climbing are your top priorities. Features unique to this shoe, like the knit top, add breathability. Durability is in question since this knit hasn't been put through the ringer, but time will tell, and it seems to be more durable than one may think.
Conclusion
The new Black Diamond Momentum - Kids is the kind of shoe that will work for most kids. For those who are looking to seek out lots of crack climbing or those that are working overhanging routes, we would recommend looking towards the Evolv Venga (cracks), the La Sportiva Maverink, or the Evolv Ashima (steeps).
