The 150 rpm is better for 2 reasons. 1. 150 rpm archetype has better inherent dps. 2. 150 rpm has better synergy with Spike Grenades because a higher percentage of its damage is from direct hit damage, which is the portion of the damage that is buffed by Spike Grenades. Also remember that best radius shifts damage around. The higher the blast radius, the more damage is shifted from the direct hit and into the aoe explosion. The lower the blast radius, the more damage is shifted from the aoe explosion and into the direct hit. Since Spike Grenades buffs the direct hit damage and not the aoe explosion, you want the lowest blast radius possible to shift as much damage into the direct hit as possible. Side note: the only reason people have such a boner for Swarm of the Raven over other 150 rpm options like Outrageous Fortune is because Swarm is void, which has synergy with Tractor Cannon.

Any aggressive frame rocket or grenade deal slightly more base damage than the other frames. Spike grenades only offer a 2% damage buff, but implosion and black powder also offer a 2% damage buff.

Swarm. Slightly lower damage for higher total ammo and a faster RoF.