The MDR-100? Well, that comes in two models, wired and wireless. I’ve only tried and reviewed the wired model.
The MDR-100 is a comfier headphone, with more room for your ears and a slightly lower-profile headband shape. It’s also a much more balanced headphone, so if you care about accurate sound reproduction, the 100 is a better choice. Of course, the wired 100 doesn’t have the noise-cancellation features of the XB950N1.
The wireless MDR-100 has the same noise cancellation as the XB950N1, so it’s down to whether you want the goofy bass features, or not.
If you meant the 1000X, that’s a better headphone overall with much better noise-cancelling, but it’s more expensive, and not as thumpy in the bass department.
If I were trying to pick between the wireless MDR-100 and the new XB950N1, on most days I’d reach for the MDR-100, based on my experience with the wired model. It’s a more capable, more neutral headphone. But if you need fun bass features, get the XB950N1!
Hope that helps out, they’re very different headphones and a little hard to directly compare. Thanks for reading!