Epic Battles of 40K: Centurions vs Broadsides

My main army in 40K is Space Marines, specifically the Black Consuls chapter. Most of the time I play them with allies, either Tau or Grey Knights. My Tau army isn't very big (yet) so I don't have many options. However, I do have 3 beautiful Broadsides that spam shots everywhere. They're a very good HS unit with Twink Linked weapons that can cause a lot of damage. I always play them with High Yield Missiles, Smart missiles and Early Warning Override (interceptor). 3 Colours suffers them all the time, and there's not a game that he doesn't say "I f$#%ing hate Broadsides".

But, on the other hand, I also use Centurions. Every single game that we play, he runs away as far as possible from my Centurions. Their Grav Cannons with Grav Amps(re rolls to wound) are to be feared. Without mentioning that with the omniscope on the sergeant, he can split fire. I always whine about their "short range", but to be fair, if it was bigger, they would be way too OP.

In a 1vs1, obviously the Centurions would win because of their AP 2 weapons, but...what unit do you find more useful for your army? Which one do you think is better? What can cause more damage? I think this is a close one.