I've had the Level U Pro's for almost a year now. Listen to them everyday at work and they are by far the best bluetooth headphones I've ever had...possibly the best headphones I've owned period... that said, I've never really spent any significant money on headphones and have limited experience. To date the only bluetooth units I've tried/owned are the Level U Pro, Jaybird Freedom (1st gen with Comply foam tips), Jaybird X2 and Motorola S9 and the Level U Pro's are in a different league.
In terms of wired headphones I've listened to dozens, ranging from something you'd find at Walgreens to professional studio equipment; I'm no expert but I know good sound when I hear it.
Sound Quality: It ranges between good to great depending on some variables. Overall I would describe the Level U Pro's sound as balanced, crisp and very clear. I don't think you'll find a better sound for less than $100. The mid-range response reminds me most (don't ridicule me for this- I have limited points of reference) of Range Rover's latest Meridian Stereo where the mids seem punchy and far more prominent than I've experienced from in-ear phones; more like something you'd expect to find from a much larger over-ear driver. Bass is very sharp, not boomy or drony like most in-ear phones seem to be. Maybe controlled is a better word than sharp to describe the bass; it's powerful without being in your face or exhausting but it also seems to be lacking in the dynamics department... I don't really know how else to describe it. The bass isn't muddy as some people have reported, but there are some times that it seems Samsung tuned them to hold back in an effort to avoid over-articulating the drivers and causing distortion... which is clearly working because I haven't detected any bass distortion to date. If you prefer very heavy, booming, bass, these might not be for you as I have noticed that in some cases (mostly classical music) the bass seemed to be slightly less prominent when comparison to my Sennheiser CX 300 II's. But if you want wireless headphones with great, balanced, higher-than-usual sound quality that you can enjoy all day, these are probably your best bet.
Samsung's UHQ upscaler and other adjustments: I use mine with a Galaxy S6 which has Samsung's UHQ upscaler (a feature that is unique to the Level U Pro) and the upscaler really does make a difference. For example, I've heard John Lennon's Watching the Wheels hundreds of times and never noticed the synthesized accordion in the background during the chorus, but it was clear and crisp with the UHQ turned on; as if the software had isolated the sound. It seems to highlight some characteristics of songs that I haven't noticed before (generally) without taking away from the balance. Sometimes the UHQ will isolate a very unpleasant sound, usually a high pitched synth or something like that and it'll drive me crazy; so somedays I'll leave the Tube Amp Pro effect on with the UHQ to soften those highs and that generally does the trick... until I get to a song that seems muffled because of the Tube Amp effect and I'll just turn off both effects.
If you don't have a Samsung phone, I don't think you'll notice any short comings with the Level U Pro's but if you do have a Samsung, I still recommend the UHQ because 95% of the time, it's excellent.
Noise Canceling: I'm fairly sure the noise cancellation only applies when making phone calls and not while playing audio... but that's just because I can't find where that feature is advertised. In the real world, there have been several instances that someone I work with has scared the crud out of me because they've had to tap me on the shoulder to get my attention. You can't hear a thing with the Level U Pro's on. If you select a well fitting tip (I'm still using the silicon tips they came with, but Comply foam is very good too) you'll feel like you're wearing earplugs if nothing is playing. Edit: Just realized there's a new version of the Level U Pro's with noise canceling; I don't have those and can't tell you anything about them but may end up buying the new version and I'll let you all know how they compare if so.
Battery Life: They advertise 9 hours... I don't know what I'm doing differently, but I plug them in once or twice a week... tops. If the battery is low before lunch, I'll plug them in, go to lunch and they're usually good to go for the rest of the week by the time I get back. VERY GOOD battery life and the charger uses the same micro-USB connector as my phone (a big plus).
Comfort: Very comfortable. I was skeptical of the on-neck design, but for work, it's perfect. My Jaybirds are much better for the gym but throughout the day the noise caused by the cable rubbing on my shirt collar drove me crazy. The on-neck design completely eliminates that cable-rubbing noise (whatever thats called). That said, I wouldn't use the Level U's at the gym... the on-neck portion will bounce all over the place while running. That's really the only thing I'd like to see Samsung address; maybe if the on-neck portion could be tightened on your neck?? But, for flights, at home, at work, studying, other low movement situations the comfort is excellent.
Other features I like: Something I didn't realize before buying was that the earphones (the part you actually put in your ears) are magnetic and will pause whatever you're playing when they connect magnetically. So when someone walks in my office I'll take them out of my ears, connect them so they're out of the way and my song will pause. When that person leaves, I put them back in, tap the play button on the end of the "U" (part around my neck) and I'm back where I left off. I also use the Level U Pro's at home with my Amazon Fire TV (so that I don't wake my wife or baby) and the magnetic tips/pause feature works with the Amazon Fire TV as well.
I think I covered everything... happy to answer any questions.
