Primal kettlebells are kettlebells that are molded into different animal faces. Specifically the animals are all types of monkeys, apes, and orangutans
These are made by Onnit (although you will also find some non-branded ones from discount manufacturers). For the most part, you will not notice a difference between the two, although the Onnit ones are much more “to spec” and have a bit better feel to them
I’ll make this decision pretty simple: if you do NOT like the way they look, don’t even bother with these. They’re more expensive and offer no additional functionality
If you do like the way they look, there is only one decision you need to make. How versatile do you want your kettlebells to be? With the face markings and different sizes/shapes, if you’re doing some exercisss (e.g., turkish getup, kettlebell bench press, etc.) this style kettlebell can feel a bit awkward compared to the standard, round kettlebell. It doesn’t mean you can’t use them for this purpose, it just means they will feel a little different (and that might bother some people).