I don't use any of the attentive phone settings. I was using Pocket Mode but ring volume is already pretty loud without it. Between that and the vibration using Pocket Mode didn't seem worth it.
I disabled all of HTC's custom Windows Phone settings aside from the extra camera features. They are mostly buggy. SRS sound enhancements cause stuttering at times, some settings may cause slightly higher battery drain, and at least one person reported better call quality after disabling the flip for speaker setting.
I wouldn't be surprised if one of those settings wasn't causing my proximity sensor to stop working on many calls over 4 minutes. I will try disabling.