You can go look at Nokia's list of apps in the store.
Other than that, you'll also not have glance, call and SMS blocker, and that new Microsoft mobile gestures thing that just came out.
HTC phones already have most of the gestures anyway, the One M8 has dot view which is decent, the hardware camera refocus is pretty good, and the M8's digitizer works better than Nokia's super sensitive touch. The front facing stereo speakers are really a bigger bonus than I thought they'd be- before I heard them, I thought, "meh all phone speakers are bad these won't make any difference". It makes a difference, and I will definitely be adding front facing stereo speakers to my list of must have features on a phone. I haven't been so floored to hear stereo audio in a long time
. Was utterly shocked when watching a YouTube video and I clearly heard directional audio.
Think of it this way; people want higher resolution screens, but somehow higher resolution audio and better audio quality in general aren't as important? Bad logic. The speakers on this device vs other phones is like a 1080p screen vs 480x800 resolution display. The improvement is there and appreciable, and very nice to have.