You can "ruggedize" your smartphone with many decent options and for cheap nowadays. I have dropped my older smartphone in the Otterbox Defender case many times as well - still working and looks like new. The new one have a hand/neck strap, attached to the Otterbox (DIY), and a "bulletproof" belt clip - never dropped it yet, but pretty sure it will survive almost anything a dedicated unit could, as I have a good habit already of protecting it at all times (too many survival tools on it). I know about the "redundancy" argument, but I prefer the "perfect single all in one, compact, lightweight tool, which I can protect the best I could" paradigm.

The "Only 24 hours with GPS on" - is not true anymore, get to Airplane mode, turn all power saving options, and don't use the screen too often, - you'll get the same time as a typical mapping handheld GPS, but way more functionality in the palm of your hand. There are plenty of on-the-go recharging options too, which are more efficient than just an AAs pile, when considered hiking weight wise, as well.