I lost my Sennheiser CX 500s which I was very enthusiastic about and since I can't buy them anymore I opted to try out something new. These are very, very close. I needed something I could workout with and the Sennheisers, coupled with the right ear tips did a decent job but these things top them. When you take the time to fit them, these fit comfortably and securely and handled a circuit workout followed by a session of sprints nicely. Not even a hiccup. The decent amount of extra ear tips in styles and sizes aided in this. So why not 5 stars?The sound. It's the most crucial part of any earbud and these things are, for the price point, magnificent. It's flatter in a good way compared to the JVC HAFX1X which I also picked up at the time. Instrument separation is good. Vocals sing loud and clear with these and the highs are high enough without being piercing. The lows are decent, punchy but not impactful. However the mids can be a bit muddy. You don't notice it as much if your music isn't so bass heavy. Indie pop, classic rock and any Hans Zimmer film score are awesome with these. You will notice it if your playlist is peppered with dubstep and deep house but only slightly and only if you're looking for it. It isn't jarring at all so it won't distract you but it IS there. I only know this because the sennheissers I lost handled all forms of electronica slightly better. As for noise isolation I will say these do a good job after a proper fitting. Another big reason I'll praise these is that even with excellent noise isolation, the soundstage of these are amazing. It's clear, wide and airy unlike some sets that sound narrow and confined, like your listening to music in an elevator.The build is top notch as well. The cord doesn't feel cheap and the angled audio jack flexes nicely without feeling like its going to break. The ear tips are soft and pliable enough for a secure fit and don't chafe my ear canal like some textured, rubber, 3rd party tips I wasted money on once upon a time. Couple that with a carrying case thats also well built as well as functional and you've got the best sub $20 set of earbuds this reviewer as found. Hopefully, after a bit of burn in, the mids will improve but even if they don't I am immensely satisfied.Update: Bought a second pair cuz I lost the first one when I got hit by a car lol. I'm thinking that the first pair was faulty cuz the new pair has no issues of the previous one. It doesn't drop connection to the phone while on a call or when playing music and phone is in a back pocket of a cycling shirt. I also noticed a nice feature and that is it stays active while charging! So I'm thinking of getting a 90 degree micro usb cable, clipping it to the shirt then dropping it down to the back pocket with a small battery pack (which I already have). This way if I have a long ride I don't have to w8 for the headset to charge, just connect the battery pack and keep listening lol (the built in batteries only last for 5.5 hrs of continuous play at low volume :c). Hoping these will last long because they've been discontinued and the x5 ones are the same (except they come in gun metal color lol I did ask and someone from MEE replied and it literally only differs by color and x5 doesn't have the carry pouch) but more expensive.Old Review: The first thing I've noticed was the amount of seal these things provided! It's hard to hear almost anything beyond music when you have these on! Usually I'd set the volume pretty high on any other headphones I've used before, with these its around 30% very rarely more than 50% depending on the type of track. Most of the time I'd listen to music (Drum n Bass, ChillStep etc ) at 10% or below. Not very good for running- at least not to my comfort lvl. When running the control and battery section of the headphones are too high and yank on my ears too much. The neck cable moves around too much and gets uncomfortable pretty fast- to fix this I've used hair pin to attach the middle of the cable to the t-shirt collar in the back. It has poor signal range- sometimes gets disconnected in the front pocked. Poor connectivity is very apparent with phone calls (not so much with music). Longer call durations will make the piece disconnect and try pairing again :/. when I ride my bicycle I put my phone in the shirt's back pocket (lumbar area) and even with music play only I get short disconnections where the track will go silent for less then a second and then the volume comes back up slowly. Overall it's still better than sony sbh 80 which worked for 6months and just died, and cheaper too lolI've been searching for a pair of headphone for running since my JVCs gave out and was struggling as I have small ears and ear canal. I really wanted blue tooth but have ordered two pairs and none fir properly in my ear and I struggle to keep them in whilst running. I found these recommended through a running magazine and although not Bluetooth, decided to try them. Well so far they are perfect. They come with a huge range on ear bits to fit every ear. They are light and really comfy. I've only used them for running once so far but they were great, I didn't even feel like I had them on.I much prefer my old JVC in ear items; which I sadly can't find a replacement for.Poor fit; for me the "over the ear system" would be fine if they were a more snug fit and sealed in more music.There is WAY TOO MUCH sound bleed from this item for my liking, the next step for me would be a custom fit item - a Christmas treat to myself :0)Bought these following reading reviews on amazon. Used them 3 times. They are ok, but no more than that. They stay on you ears but not in them. Volume and sound is low. Used JVC ones in the past, a lot cheaper, and they were great. I'll go back to them next time.Usually in ear headphones hurt my ears because there always to big but these are a perfect size. They even stay in place when I'm running. Sound quality is good and overall I,m very happy .brilliant fit and great for the morning jog