I've gone with a mixed build of weapons and range, using C-UAC20 (3 tons of ammo) in my left arm for that crazy dakka, x2 Heavy Medium Lasers to get bang for the buck and x2 C-SRM6 Artemis (2 tons of ammo), one in each shoulder. And 3 extra heatsinks.
Do go for Omnipods with Armor bonuses. Laser arms do not have any quirks but the Ballistic arm (MDD-C) has +20 armor while shoulderpods (MDD-PRIME) have +15 armor each and! missile cooldown and missile velocity quirks.
Until you invest into Operations (for heat managment) and Firepower (for minor heatgen and all AMMO NODES!), you will run hot easily and find yourself running out of ammo relatively easily.
After you've unlocked these nodes you will find it that while you can still run out of ammo, in such rounds you'll have done plenty enough to contribute greatly to the team.
As for the skills, I chose to go with little over half of firepower tree (some bottom HeatGen) to get those missile and UAC nodes. Skipped Survivability as gains from it would have been minimal but I did invest heavily into Mobility tree to gain extra speed, acceleration and deceleration. After all, this is both a brawler and hit-and-run mech so being able to get in and get out as well as being able to stop or gain speed swiftly is a major deal. This also means you can keep up with most mediums mechs, mechs which cannot carry similar firepower. Going 87kph as well as having excellent forward/backwards in a heavy is quite comfortable and fluid. And of course, full heat managment in Operations.
This is the build if you wish to try it out for yourselves and let me know how it works out for you
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