I have seen enough bad reviews about this product but honestly its too good. I have purchase yellow variant from amazon.in a month ago. I am not an avid user due to time consistency but use it for my leisure only. So, technically you can call me a mild audiophile but when it comes to earphone I am a big fan.
Design & Looks - Logitech X100 is made of high quality plastic material(ABS I guess) and outer is covered with rubber. It can prevent damage and accidental falls. Also, the product might never get visible damage due to it. However, the rubber material gets dirty easily. You can just wipe it out with wet cloth.
Music Performance - Music quality is good and pleasant. Bass on mid is low, bass on high is deep, treble is very satisfactory. Yeah, its sound volume is bit low but can be expanded by hanging on the wall(technically it works). I dont expect its sound to be very loud at such price. One more thing, you will get better sound loudness while using with PC then Mobile.
Mic - Never used it to receive calls. So, cant help.
Compatibility - It works with iPhone, Android, Laptop, Computer with bluetooth dongle/card, Featured phone with bluetooth, Any other device with AUX.
Battery backup - The day it delivers to me I played it for around 2-3 hours without having any idea of battery percentage. The only thing it lacks is battery indicator with bluetooth. As per my experience it can go around 5-6 hours of playback with standby and close to 4 - 5 hours of continuous playback. All you need to charge is for 2 hours to achieve such playback.
In the Box - Manual, USB cable, Speaker.
Warranty - Trust me, you don’t need it at all. However, avoid VLC player to avoid any chances of distortion.
Sanctification rate - 9/10.
Reason to cut out 1 point is that because of its loudness is low. Anyway, all other elements are too good and balanced as per its price.