I'm wondering if the design of the 4th gen nano case is flawed, and I'm running into early adopter issues.
I swim laps with music, so I bought this for my nano as soon as it was released. I swim in a fairly leisurely manner (no depth or kick turns or anything fancy) for about 45 minutes at a time. I noticed that after swimming, my case would be kind of humid inside. After several weeks of this, I actually found water droplets on my nano. I contacted the company and they sent me out a replacement immediately (excellent customer service). The front side seal on the new one was different (grey instead of white). However, I've noticed this one starting to do the same thing; water droplets in the vicinity of the clickwheel. I also just noticed what looks like a scratch but could be a crack extending from the top right corner of the clickwheel out to the edge of the surface.
The wheel is also extremely non-responsive through the window. I have to actually be looking at the screen in order to use it, so I can see when it's recognizing input and when it isn't, which is inconvenient considering that I have difficulty getting it placed on the back of my swimming suit top in the first place. I wish the inside of the clip tapered so it would simply slide on, but it's blunt and catches the edge of whatever you want to clip it to