Well on dreads on speeders no not IMO. While some say the cyclone ML is better on termies I disagree against the standard T4 squad its 4 shots vs 2 shots both need 2+ to wound and 1 has rending to ignore some armor. and on non T4 stuff if it has a 2+ save assault cannons are still better. If it has a 4+ save assault cannons are still better because of more non saves. Even against monstrous creatures it will end up being approximately the same. the only thing the ML has on the assault cannon is range.