Regarding my earlier comment back in February...
I used Wahoo Fitness, a complete freebie, and enjoyed it. Simple, fast, very basic, with auto-pause/restart. But it was too limited and couldn't show or share the data I wanted with other apps. It's a good freebie for folks who just want something very basic, simple and fast for an older iPhone.
...turns out Wahoo Fitness will communicate complete data to Strava. So while Wahoo Fitness doesn't show much data within the app, it does record it and can share it to Strava and other apps.
That's handy because Wahoo Fitness displays speed much larger and more readable on my iPhone 4s, so it could be useful for realtime monitoring if I used a handlebar mount (I don't for now).