I think the second one looks great, but the first, light turret looks too similar, like someone simply plucked out the two flanking barrels and called it a light turret. 
That's pretty much it. The single one is supposed to be a 'light' version of the sccond, to be fitted on smaller ships that dont have the ammo capacity to use a triple-barreled turret.
You might like this though: another new, general purpose-effective-against-anything turret.
[sales pitch]
Being hit by fighters that evade too well? Hit them with double flak cannons that spew shrapnel in a wide area! Or even better, launch missiles and watch them dodge
that! Being annoyed by that pesky shielded bomber that flies through your perfectly clean carpet of flak? Blast them away with the top-side laser cannon! Got a gunship that's coming a wee bit too close? No problem! Just activate the side beam cannons and it's history! All this with teh new Scary Turret v5.3! Now with self-shield generator and enhanced armor plating for better defense! Order today!
[/sales pitch]
