My HTC One has been a mixed blessing. Here's some notes that might be helpful to you in configuring and running it.
Honestly, you should probably just run CyanogenMod. I have run it on previous phones, and really like it. You'll lose Beats Audio, but somehow I think that's livable: get a good equalizer app and you should be able to get about the same sound.
Still, if you're going to stick with HTC's Android load:
If you want to use a third-party keyboard such as Swype, you'll need to disable the HTC One Sense Input keyboard, as it keeps reinserting itself as the default keyboard. Go to Settings/Apps, then go to the right until you get to All (easy to miss), then find HTC One Sense Input, then disable it.
You won't be able to use most (any?) MTP clients with the phone while HTC Sync Manager is turned on, which it is by default on my phone. Got to Settings/Portable Hotspot and Tethering and find HTC Sync Manager to turn it off.
(B)