1) The sound of the WF-C510 is really good right out of the box without EQ. I listen to a lot of music, various genres, and everything is balanced and in control. Punchy bass, treble that's crisp and doesn't make my ears bleed, and decent mids. I definitely trust Sony when it comes to audio products.2) Fit and comfort are amazing! I can leave these in all day. No joke, after 5+ hours of use, I feel zero discomfort. Not only are these earbuds the most comfortable earbuds of all time, but getting a good in-ear seal is effortless. Just set them and forget them, zero hassle. Just to note, there's no ANC but I don't mind; I use these at home where it's already quiet. Further, there's a feature called Ambient Sound Control, kind of the opposite of ANC, that lets outside noises in (press button on left earbud). Obviously, the volume has to be pretty low for this feature to be useful.3) I rarely ever use playback controls on a pair of earbuds, as I just use my phone for that stuff. However, the physical buttons on the WF-C510 work like they should and it's always nice to have actual buttons over touch controls, mainly because there's less chance for accidental inputs, a common occurrence on my other earbuds.4) The battery life seems to jive with Sony's claims of 11 hours in the buds and another 11 in the case. I'm getting a 50% battery level after 5+ hours at a volume level above half with the "Sony Sound Connect" app installed on my phone. I'll admit, the 11 hour battery claim was the #1 factor for my purchase.5) The app gives you a ton of stuff to play around with. There's a bunch of EQs, 360 audio (more app downloads and payment required, I think), information regarding battery levels, and more.6) A couple of oddities: The charging case confuses me. Does the orange light turn off when charging is complete or does it stay lit? I've experienced both scenarios and both times the app said the earbuds and case were at 100%. The instruction manual was no help. Also, for some reason I had to re-pair the earbuds to my phone's Bluetooth after shutting it off, which was super annoying. I was testing to see if an older device (without the app) would pair, so to avoid interference I turned off my phone's Bluetooth. The older device paired with the earbuds just fine without the app, so it isn't required. I plan on deleting it; it's probably a major battery hog anyway.7) Minor issues aside, the Sony WF-C510 delivers premium comfort and pleasing sound. and they're super affordable. Get yours today! lolUpdate 3/25 -- Checking in to mention that the orange charging light on the case does in fact shut off to indicate that charging is complete and I'm still very happy with my purchase.