Buy the Refurbished AirPods if You Want Action Earbuds
This is all a matter of preference, really, but I personally would prefer the AirPods for sports. Why? Because they sit snug inside the outer lip of your ear instead of being forced down your ear canal. This means that they have a smaller chance of falling out, and don’t become loose with movement. Can they fall out? Yes, but in general I feel these are more comfortable for sports and extended wear.
And since a pair of used AirPods doesn’t form a seal inside your ear canal, you have a better idea of what’s going on around you. What I love about AirPods is when I’m biking around the city; I can still hear my surroundings crystal clear.
And even though a pair of used Sennheiser Momentums will give you an ambient sound mode that allows some ambient sound to be transmitted into your ear, I still prefer the classic AirPods design if I want to hear what’s going on around me.
Also, I feel that AirPods are generally more comfortable for longer periods of wear, at least for me.
Also, AirPods are generally an easier fit for most users. Since they don’t need to form a perfect seal inside the ear, you don’t need to worry about changing out rubber earpieces to fit your ear canal. AirPods are a one-size-fits-all kind of deal.
AirPods Pros sit inside your ear just like the Momentums and also have an ambient sound mode, but are known for having a lot less bass than these sweet Sennheisers :)