I actually did a full factory reset last night after reading similar information on the how 5.0 changed from dalvik to art and many have benefited from either clearing the cache or doing a full reset and letting the apps rebuild themselves. On my specific device it was recommended that one disable the newer NuPlayer which was labeled as experimental. There were issues reported of how this conflicts with the facebook app when processing sounds. The downside for many is that the facebook app can't be uninstalled because it was part of HTC's Sense customization.
Overall my phone is feeling more responsive so far but I've only had a day to play around with it after the changes. I'm still unsure of the battery life changes yet because I haven't had enough time with the reset. One other item that plagues the AT&T edition of my phone is a bug in their software which constantly uses the GPS. The GPS light flicks on many times a day for long periods of time. I've read of many others with the same complaint and AT&T has yet to fix the issue.
Overall my phone is feeling more responsive so far but I've only had a day to play around with it after the changes. I'm still unsure of the battery life changes yet because I haven't had enough time with the reset. One other item that plagues the AT&T edition of my phone is a bug in their software which constantly uses the GPS. The GPS light flicks on many times a day for long periods of time. I've read of many others with the same complaint and AT&T has yet to fix the issue.