I have the Otterbox Commuter case on my HTC One, and I love it. It fits perfectly on the phone and does protect it well. About a month after having the HTC One with the Commuter case on it, I actually dropped the phone on a concrete sidewalk, and the phone is fine. Also, there were no scratches on the case either, only a very minor nick on the rubber bezel.
Personally, I also feel that the Otterbox Commuter case makes the phone look professional.
As for holsters, I did have a few problems finding a holster that fit. With the help, however of one of the nice members here, I was able to find a holster that fit on Amazon. If you like, I'll look for the link and post it.
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