I've been through the cycle. Stock Apple silicone tips were easy to pop in and out but would slowly work their way out of my ears throughout the day. Switched to Comply foam tips, which solved the fit problem but introduced a new annoyance: having to squeeze and compress them every single time I put them in. They also degrade after a few months and need replacing. I wanted something that sealed like foam but inserted like silicone, with no prep ritual.
The XELASTEC II nails it. The TPE material feels like a slightly tacky silicone when you put them in, so there's zero compression or fuss. You just pop them in like the stock Apple tips. Then within about 30 to 60 seconds, your body heat softens the material and it molds to the exact shape of your ear canal. The grip is unreal. Chewing, talking, working out, head movements, nothing budges them.
ANC performance improved noticeably over the stock tips because the seal is tighter and more consistent. Bass tightened up and the overall sound became cleaner and more detailed. The urethane-coated adapter is a nice touch that prevents the micro air leaks you get with cheaper third-party options.
Sizing is way more granular than Apple's, with six sizes available. I'd recommend grabbing a multi-size pack so you can find the exact fit for each ear.
Only caveats: clean with water only (no alcohol or soap, it damages the TPE), and the surface attracts lint and dust, so keep them in the case when not in use. They're pricier than generic silicone replacements, but they outperform everything else I've tried by a wide margin. Foam comfort and seal without the foam hassle. Highly recommend.