GPS? No thanks
I'm a distance runner and I do not use GPS, I have a Polar watch with a footpod for speed/distance and a heart rate chest strap (pretty robust). I have trialled GPS by taking my phone in an arm wallet and have issues. I live on top of a hill and am wont to run up hills, the steeper the better on most of my runs and GPS is not good with slopes, it does not speak Pythagoras well, a point against.
I also have the mainline to Aberdeen between me and the waterfront and the A road cycle path also does a long underpass. Even when I'm going over the rail line on a footbridge GPS fails. There's one with a switchback ramp and I run beside it before getting on, so three 10m passes beside each other and GPS tracks one. My footpod logs every footstep. Another point against.
Even if we somehow discount the loss of contact and lag regaining it causing inappropriate straight lines to be drawn when going under things there is another issue. There are lots of high walls around here, retaining walls on the hills and behind properties with roads front and back and the GPS is wont to drop out against those as well. There is one just as I turn off the main road to get home. GPS has me running straight through a house because of this. Another point against.
I have runs where all these issues come up, in multiple and meanwhile my footpod logs every step. If you live on the Iowa prairie I can see GPS tracking being a boon, in lumpier, more forested and built up areas, not so much.