Comfort is mostly good, but there are things you should know before buying.
The basics are solid. At 254 grams, the XM6 is light for over-ear headphones. The headband spreads weight well, and the overall feel on your head is pleasant.
The earcups are the issue. Sony kept the same shallow design from the XM5. The padding is thin, and the interior space is tight. If you have larger ears, they'll probably touch the driver housing inside the cup. This isn't painful, but it can get uncomfortable over time.
One specific annoyance: The ANC microphone inside each cup sticks out slightly from the mesh. Some people feel it pressing against their ear during long sessions.
About the clamping force:
Out of the box, the XM6 clamps firmly. Sony did this intentionally for better noise isolation. The trade-off is they feel snug at first. After a few weeks of regular use, the clamp loosens.
For glasses wearers:
Good news. The Adaptive NC Optimizer adjusts for glasses automatically, so you don't lose much ANC performance. You'll feel some pressure where your glasses arms meet the ear pads, but it's manageable.
Realistically:
Most users can wear the XM6 for 4-6 hours without issues. For all-day wear, take breaks. If comfort is your absolute priority, the Bose QC Ultra has deeper, plusher earcups.
