Having been a runnist and a cycler for over 35 years, I can say that of the two, running is much more preferable. You get fitter faster being the main benefit. A 40 minute run is ideal but a 40 minute bike ride? Wasting your time going out. Running is a lot more sociable. The race winners, especially fell runners, will happily chat with the last runner in great cameraderie but in a cycle race/sportive/duathlon, the winners happily ignore you and if your bike is inferior to theirs, beware. I'm not talking about on here, by the way. I've met loads of sociable people off here but I mean in competitive events only. Of course, you can do too much of anything and that's what I did so all my overuse running injuries means I have to get out the bike. Don't get me wrong, I love it and it's great but having extensive experience of both, I'm more a runninst than I am a cycler.