Goal - go fast or go long

SpleenThief

I've got a running background but it's been a few years since I've been consistent. For my workouts I'm training for a triathlon and I'm looking for some input on where to set my sights.

1. Keep it shorter (Olymipic Distance) and go for speed.

2. Go Long (Half Iron Man)

When I was running I became enamored with the marathon and have done a few. However as I ran more I was curious to see how fast I could get. I think a sub 20 min 5k is more impressive than a 4:30 marathon. so maybe I'll stick with the shorter distance and see if I can really nail one. Training 12 hours per week should yield a pretty decent time on an Olympic distance but a mediocre Half Iron Man

However going long can be pretty cool.

I know I'll get a mix of responses so just let me know your opinion and why you have that opinion.