Just saw this thread. I've spent years testing gear for endurance training and honestly, flagship models often trade durability for features. In my experience, the moisture seals on those high-end units aren't built for marathon prep. I actually ruined a pair of expensive Sony buds a few years back because they just couldn't handle the salt. Technically, you're better off looking at the Sony LinkBuds S Noise Canceling Earbuds. They have an IPX4 rating for sweat and they're much lighter than the XM5s, which helps them stay put during sprints. Over the years, I've found that a lighter bud always beats a bulky one for running. Another great alternative is the Sony LinkBuds Open Ring Earbuds. These use a physical wing support that locks into the ear ridge, providing a much more secure fit. Both options are way under your 300 dollar limit too.

Honestly, unfortunately Sony really dropped the ball for heavy gym use with their flagship line. I have had issues with both the Sony WH-1000XM5 Wireless Noise Canceling Headphones and the newest buds when things get sweaty. Whatever you do, dont get those over-ears for cardio. Those pads are basically sponges and since there is zero IP rating, you are just asking for a hardware failure or at least some nasty smelling pleather. Its not as good as expected for the premium price. The Sony WF-1000XM5 Truly Wireless Earbuds are a better bet but those foam tips are finicky during sprints... they tend to wiggle out once you start sweating hard. Switching to the Sony LinkBuds S Noise Canceling Earbuds IPX4 for marathon prep was the only way to go. They are way lighter and stay locked in better during high-impact movement. The ANC is a step down from the flagships, but they actually survive the workout and wont fall out mid-stride.

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