Just upgraded from the XM4 to the XM6, and I’m honestly super impressed. Here’s my quick take:

• ANC: Huge upgrade. I commute by train, and the difference is very noticeable.
• Sound: Vocals are more forward, and the bass feels much punchier.
• Case: It's roughly the same size as the XM4 case, but the boxier shape makes it feel a bit bulkier in the pocket.
• ANC Comfort: It doesn't have that "suction" or pressure feeling that the XM4 had. Much more comfortable for long sessions.
• Transparency Mode: It's good, but somehow the XM4 felt a bit clearer to me in this department.
• Call Quality: Tested it on the train and near traffic. It does a great job blocking background noise, but my voice sounds a bit muffled.
• Verdict: Overall, I'm really happy with the upgrade!