For this review, let's cut to the chase. Don't buy the Sennheiser CX5.00G headset. Audio wise they're not bad, but having gone through two pairs of them in the last year, I simply cannot recommend them. In recognition of this fact, rather than showing an unboxing, here's some photos of the reboxing, just prior to them getting sent back to Amazon. It should be noted that Amazon have been absolutely amazing when it comes to their customer service. They replaced the first pair, and this time gave me a full refund.
The initial impression I got when I first bought these in March 2015 were that they were a premium product, and the reviews reflected this. The build quality felt first rate, and using them was a pleasure. The silicone rubber tips were a little annoying, but once sized properly gave a good degree of passive isolation. Now that we've dealt with the positives, let's get back to some more negatives. Those rubber tips are held onto the metal speaker cone by nothing more than friction. This works well when the tips are new and quite stiff. Once they've been worn a bit though, they soften. When they soften, the tips are liable to fall off at inopportune moments. To this end I had to start storing them in a bag lest I lose a tip.
By far the biggest problem though is the rubber outer insulation on the cable which has now split twice. Unlike losing the tips, which can be replaced, this effectively ruins the headset, exposing the wires inside the cable. While the splits didn't affect the audio quality at the time of sending them back, if the splits had grown, catching the cable could have ripped it in half. Unlike the headset, I can't complain about the Amazon returns process though. Having gone through the process where they phone you, I spoke to a customer services rep. They quickly processed a full refund with free return postage. They also withdrew the headset from sale until they can investigate whether this is a wider issue.
So, the Sennheiser CX5.00, don't buy it, it's a pain to live with. But what to replace it with? I need a good quality headset with microphone and Android compatible remote control for less than £70. Suggestions in the comments below please.