Seriously slimmer design, larger screens ( tho i prefer a 5" phone and 1080p resolution) HTC might nail this one once again, tho also im not sure since its slimmer we might see another bend issues here i surely hope none..
HTC One M9 (another rumored specs) kicking of with Snapdragon 808 Dual-core ARM® Cortex™ A57 and quad-core A53 with 64-bit support, Adreno 418 GPU, 3g of RAM.. other from this day we have seen some rumors that HTC One M9 will be equipped with Snapdragon 805 which is a 32bit "and" cannot fully use/utilize the 3g of RAM equipped on it.. "hopefully" we'll see it equipped with this Snapdragon 808 "OR" Snapdragon 810.
http://www.youtube.com/watch?feature=player_embedded&v=MERVDot6d90
Source: http://www.technobuffalo.com/2014/11/22/check-out-this-awesome-htc-one-m9-concept-design/