HTC responds to the micro arc oxidation matter as it starts chipping out for some users. Various users are complaining about it and now HTC responds to The Verge and says that:
HTC is committed to delivering a high quality product and great experience for all our customers. There have been a few, isolated reports of this issue. The finish on the One S was laboratory tested as being at a hardness similar to ceramic. While that’s hard, it doesn’t mean it’s impossible to damage. Regardless, HTC takes quality very seriously and are providing all customers with an immediate fix and we are implementing some small changes to ensure customers do not experience this issue in the future.
Looks like One S owners who have already purchased the device could either bring the affected devices back to the store they purchased the phone from, or HTC will replace it under their standard warranty terms.