Comfort on the Sony WF-1000XM6 is generally good, but it's one of those things that really depends on your ear shape.
Sony redesigned these with a pill-shaped profile that's slimmer than the XM5, and at 6.5 grams per earbud, they're light enough to wear for hours without fatigue. The matte finish is a nice upgrade from the old glossy design – they don't slip around as much.
Where opinions split is the ear tips. Sony includes four sizes but they're the same hybrid polyurethane foam tips they've used since the XM4. For some people, these fit perfectly and create a great seal. For others, they're too firm, don't stay put, or just feel uncomfortable after a while.
Getting that airtight seal is important because it affects both comfort and how well the noise cancellation works. The fit can be fiddly – you might need to experiment with different tip sizes and insertion angles. Sony's app has a fit test that checks your seal, which helps.
If the stock tips don't work for you, third-party options like Comply foam tips are compatible and often solve the problem. Many people swear by aftermarket tips for improved comfort and a better seal.
Overall, most people find them comfortable for long listening sessions, but if you've had issues with Sony's ear tips in the past, that probably won't change with the XM6.