after weeks of research i found these buds, I have medium sized ear, like the average guy. I Did a jog with these, first the sound is very good, bass is amazing!! BUT, the sound is as good as the fit is, meaning if the buds slip a bit and not 100% secure the sound quality goes 50% down. I tired all fits possible, took me good 2 hours to try and fit all sizes with a light jog. First, it is secure for good 2 minutes than the buds always slip out, it is even worse when you start sweating the buds just cant stay in properly in your ear, when sweating even when not jogging just working out at the gym, the buds are slipping out (not falling of course), as i mentioned than you lose the quality of sound by 50%. Im going to return them unfortunately.
For some bizarre reason I was sick of my wired Sennhieser PMX 680 headphones because the band around the head makes it difficult when on the plane (or laying down), plus cables are annoying. Going from those to these headphones - what a disappointment. Unless you want to spend the whole time holding these in position, the sound is barely better than the stock Apple headphones. Connectivity drops out repeatedly when using wifi (a pain if you listen to lots of audiobooks). I give these two stars because they are very light and, apart from the constant feeling they are about to fall out, they are very comfortable, also because there is barely any cable they are so much easier to transport. For now I'm sticking to my wired Sennheisers. I simply cannot sacrifice the sound for comfort.