One of the most significant issues with the OtterBox Wireless Power Bank for MagSafe is that there is no stabilizing line underneath the magnetic circle. Because of this, the battery pack itself is quite prone to sliding around, especially if you put it with your phone in a pocket.
The hard plastic has no grip, and since there is no stabilizing line, this battery pack can move around quite a bit while on your iPhone since the magnetic hold isn't very strong.
The magnetic hold on the OtterBox Wireless Power Bank for MagSafe is also just not very strong overall, so it's not just the lack of stabilizing line that is the problem. Compared to my other MagSafe battery packs and accessories, the side that attaches to your iPhone is honestly quite weak, even if you're using one of the best MagSafe cases. With such a weak magnetic hold and no stabilizing line, this battery pack tends to just move around a lot, so you won't get consistent charging unless you're super careful.
I'm also not a fan of the fact that you need to push a button to power this one on unless you slap it onto your phone right after charging it up. For my MagSafe battery packs, I prefer just to put it on my phone and have it start charging automatically — no extra button required.
Lastly, the plastic housing on this battery pack just feels cheap. It also has no grip to it, so it's actually fairly slippery compared to other options on the market. And when you pair that with the weak magnetic hold on your iPhone and no stabilizing line, it's just not a good time.