I have both a fancy Android phone and a Garmin Forerunner 305. The Garmin has the added benefit of being easily mounted onto your bike and working with a cadence sensor. No Android app lets you do that. To be honest, I never use the GPS function on the Garmin, except for when I download my workouts into the software, so I can't speak to that particular aspect, which might be what you care about more than mounting and cadence.

Either way, you'll get something great. And congrats on your milestone birthday!