First I want to talk about the Refurb factor. I was nervous to order refurbs because it often feels like rolling the dice. As a verified refurb purchaser, I can say I'm ecstatic. Mine even came in the original box with all the accessories. I was worried the battery wouldn't perform like a new pair, and that trepidation was also squashed. These function just as though they were brand new. Ecstatic with these refurbs.Now let's get to the headphones themselves. I own many pairs of headphones. Sennheiser Hd650, Beyerdynamics, and AKG 550, for example. I also have quite a few earbuds, Sony XBA-H3 probably being my favorite earbuds that I own. I love good audio and am willing to spend a few bucks for it. So what brought to buying these WF-1000XM3? The noise cancelling, true wireless, and reported sound quality. In all three categories, these are amazing. Packing all this in such a small and attractive package is a remarkable achievement. Sony basically created the active noise cancelling true wireless IEM market with these headphones.Noise cancelling: Best in the business for IEMs. You gotta get over-the-ear to surpass the noise cancelling of the WF-1000XM3. These silence dishwashers, washer&dryer, air conditioner, and other ambient noises that we get used to having constantly around us. I some times pop these in and not even play music...just to silence the world. Amazing that these work so well given the small form factor.True wireless: Some factors for a true wireless that matter to most consumers are battery life, water resistance(IP rating), and latency(when viewing videos). Battery life is really good. They last as advertised and sometimes longer at lower volumes. Comes with quick charge. Won't find better battery performance from any other high-end active noise-cancelling IEMs. Water resistance isn't listed. These do not have an IP rating. I have used them in the gym, but I don't really sweat much until the end of my workout. I wouldn't bring them in the shower, but they should be okay in light rain or a light workout. I have a second pair of true wireless IEMs, Jlabs Signature, that I use for heavier workouts and shower(these do have IPX rating). Probably one of the most important thing for users is latency. I can report that these have no latency when used with my Galaxy Note 10 plus. Can watch a video on youtube, netflix, disney+ or amazon prime without any lip synching issues.Sound Quality: These are great. I don't think they're as good as my wired XBA-H3 or my over-the-year pricier headphones, but these are great. I played around a LOT with the EQ, and I am very happy with the sound. I would describe the sound as very precise and balanced. I can identify every sound and instrument. There isn't a blending of sounds that you can get from cheaper headphones with smaller drivers. Everything from the low end to the high end is precisely represented. IEMs in general don't provide a big sound stage, but these do provide A sound stage. I feel surrounded by the music, as opposed to feeling like the music is coming from inside my head. It's a really fun pair of headphones with which to enjoy music and video. The EQ on the headphone app works great. Every little minor adjustment does make a tremendous difference, so take your time getting your preferred sound out of these. With proper EQ tweaking, everyone from a basshead to a classical music listener should be able to achieve what they want out these versatile gems.They are a great value at full price. At the refurb price? these are an outright steal.