I've now had my One for about a month. Loving it so far. The battery life is so far superior to any Android phone I've had that it's not even a contest.
For those of you that might know me from my Incredible/Rezound days, you know that I'm not a heavy user. I disable or at least lengthen the time between updates for most apps that auto-update, since I really don't need my phone to beep at me every time I get an email or someone gets a new high score on Candy Crush or whatever. I just let it update when I actually turn the phone on and check my mail (I do have 4 IMAP accounts being checked once an hour). A typical day for me is spending maybe a couple of hours of screen on time reading/replying to email, browsing, checking Facebook, etc. and maybe 60 minutes or so of phone calls. So I'm probably not the typical user.
This is a stock, non rooted phone (for now anyway). Additionally, I am on Verizon and their network is phenomenal pretty much everywhere I use my One, so weak 4G isn't a problem.
Having said all of that, my goal with any smartphone I've had is to make it from the time I wake up in the morning till the time I go to bed without charging. I haven't even come close to needing a charge during the day with my One. Typically, when it goes on the charger before bed, it's still well over 50% remaining, sometimes over 60%. I don't ever remember not being worried about having to charge during the day, previous to this phone.
So, for those worried about not having a removable battery (I had two apiece for my Rezound and Incredible), unless you are a really heavy user, or are on a weak network (and there's not a smartphone in the world that can deal with that), it's not really an issue. The battery life is outstanding.
Hey, we're all in this together. Be good to everyone, OK?
Current devices: HTC One, Acer Iconia A500 Tab (stock ICS).
Past devices: HTC Rezound, HTC Incredible, HTC Touch Pro, HTC PPC-6800, HTC PPC-6700, Palm Tungsten C, Handspring Treo 90, Psion Revo (yeah I go way back)