The Locusts are amazing fire-support lights. I don't use mine for scouting (no ECM) and I'll tend to stick with the team for the most part or with (an)other light(s) with ECM or wolfpacking. The 169.3KPH allows it to pretty much keep up with any other light and is a great distraction with the acceleration/deceleration skills to bait an opponent.
Overall the 3M has great damage output with 5 Medium Lasers and Double Heatsinks. The 1V is a master at targeting armor-less spots on any mech with 4 MGs and shearing off components while your team mates are fighting them; including a Medium Laser for shearing armor off by yourself, especially of rear torsos while they are distracted.
The only one I'm not very fond of so far is the 3S. Missle Launchers take up a lot more room with the combination of weapon and ammo than either the 3M's Lasers or the 1V's Laser and MGs. The SSRM2's work fairly well in combination with a Laser against other lights, but are a bit on the low end for damaging heavier targets and any sort of ECM will make it difficult without anti-ECM support to even use. In addition the Locust's high speed doesn't lend itself very well to SSRM2 lock-on use and I feel is better for SRM hit and run tactics. Balancing out SRM2/4 and ammunition is a constant issue though, which I find I either am not putting out enough damage and have too much ammunition that I'm not using fast enough, or that I run out of ammunition too quickly and am left only with a Medium Laser. I have not put double heat sinks on the 3S yet though, and I'm hoping to find a comfortable median with 3 SRM2 and 3 tons of SRM ammunition in addition to the Medium Laser.
Anyways, this was a game I'd had the other day that I did really well in.
Locust 1V - 1 Medium Laser, 4 Machine Guns, 2 tons MG Ammo. (I realized I didn't have either Endo or Ferro on this Locust which is why I had 2 tons of MG ammo instead of 3.)