I know I would nearly always pick the missiles, but then I like experimental tech more than most. What say the rest of you?
LB-10X: Lowest damage of the lot, but nothing critseeks like an LB-X. The increasing combined arms emphasis along with the flak bonus also make it great against non-mechs.
Ultra AC/10: Consistent, compact, and good damage. Less likely to hit with the second hit than the HAG, but it averages out to be similar and concentrated damage is nice.
HAG-20: Great range, but damage is more spread out. Not to mention the fact that larger HAGs are strictly better since the range doesn't drop like with autocannons.
SLRM-20: Damage is clustered like the HAG but every shot hits. So, barring effects like cover and AMS, a ton of SLRM-20 ammo equals 120 damage to something. Better range than the autocannons, and the HAG takes a cluster hits penalty to outrange it.
Enjoy SLRM! It's highly effective!