Actually, a gps is cheaper than a smartphone contract if you don't
already have one - over $600/yr up here, depending on provider and
contract. (and they won't let you buy one without a contract)
Battery life on iPhones used for tracking may be as short as 2 to 4 hrs.
If I'm tracking and taking pics, usually 2 hrs is about max. It's died
several times on me. My running gps has about 20-hr battery life; while
my handheld is probably about the same and uses AA batteries so can
replace on a long trip.
I don't use cell phones usually (except for coordinating volunteers on
race or work days), but got an iPhone (and iPad) about a year ago for
trail work, map distributions, connecting kids, etc. The app for
tracking recommended to me was MotionX GPS but some others use MapMyRun
and Gaia GPS and some others. I've played with them but prefer a GPS
because of the battery life.
That said, while my iPhone doesn't take as good pictures as my camera,
it's smaller and geotags the pics, although fairly rough lat/long. My
handheld gps takes decent pictures as long as light is decent, but it
geotags them really well. What I run with now is Garmin 910xt (has
barometric altimeter for better hill data). Sometimes my phone goes
along to take pictures, but I don't have it tracking while I'm running.
When I'm after serious data, I use my handheld and camera.
I can geotag my regular camera pictures later if needed.
--
Dot
"Surrender to the run and allow it to take you, rather than trying to
control or force an outcome."