I'm in a gym 4-5 times a week, and I tend to sweat really heavily, particularly during the warm weather which we've had over the past few weeks. I typically prefer over- ear headphones when I'm in the gym, but after having realised that my sweat had caused my last pair of headphones to stop working properly- they weren't actually gym headphones- I decided to invest in some proper sweat resistant ones. I couldn't find many over ear pairs, so at first I was disappointed, but then I checked out the reviews for the in ear ones, which were more widely available. These were the choice I made, and at a much cheaper price than I would have paid for over ear sweat resistant headphones.
They're comfortable, and have loops of different sizes so that they can better fit in your ear. Connecting to your device is easy, and the headphones themselves are easy to use. Whether I'm on the row machine, trying to break records on the treadmill or going nuts on the stair master, they stay in, which is always good. My last pair of in ear headphones were good, but they had two major problems: firstly, they kept falling out due to weight imbalances. Second, the plate on the back of the earbud which magnetically connects each one together wasn't particularly durable, and so after a while of connecting and disconnecting the buds from each other, one of the plates fell off, exposing the wiring underneath. They still worked, but then I was robbed of the ability to magnetically link my buds together, which was obviously beneficial. These headphones are built much more sturdily, and the seal between the plate and the rest of the bud is very strong.
The noise cancellation is also excellent, so good that I'm going to grab a second pair for use in the library when I'm studying. I've never really been interested in noise cancellation, especially considering that people usually want to grab my attention when asking about how many sets I have left on a particular piece of equipment- but then a tap on the shoulder usually is sufficient to grab someone's attention, right? The sound quality is also good. Nothing world breaking, but it's clear and unless you are a real audiophile, you shouldn't have anything to be unhappy about.
The battery life is the only thing I might criticise (nitpicking to be honest, it's still good), but then the headphones only take an hour to be fully charged, it's a minor detail, really. A great product overall.