Regardless of which case(s) you opt for,I
HIGHLY recommend the XTREME GUARD BODY SKIN:
HTC ONE M7 Screen Protector
Along w/protection against scratching,etc..it provides for a firmer grip in-hand.
Add a bumper guard & this level of protection may be all you need.
As silly as this may sound,this is one of my favorite accessory purchases for any phone to date,including B/T peripherals,docks,cases,etc.. as it is a true accessory in that does not detract from the original form factor & adds nothing more.
Use the current "60off" coupon @ checkout & you can't go wrong.