I finished mastering them today. They are pretty solid performer once you find the rhythm, pulling 300-700 damage pretty reliably. STs almost never popped unless I got hit from behind, so they are solid for XL engines. You can run high engines for +100 kph run speeds but its not necessary if you use JJs effectively and maintain a little distance. The builds I used, w/ XL300 4xJJ in each:
QKD-4G w/ 2xLPL 2xML 1xLRM5 -- Very large number of energy weapon quirks make this very efficient. 32 point energy damage on targets that are close to you, while the LRM5 can get you some supplemental damage on close targets and contributes to the long damage swaps too. I tried using SRM4 for a while but I dont have enough agility--may work better with 350ish engine, or maybe with Streaks (but those require BAP to work reliably).
QKD-4H w/ 2xLL 2xML 2xLRM5 -- the key here is keep +180m and spam the LRM5s on chain-fire while also hitting the target with LL. It does not have many quirks, and the few it does have are limited to missiles and SRMS, so I sold this one as soon as I mastered.
QKD-5K w/ 2xERLL 4xMPL -- Very strong energy boat. 42 alpha if they are close, will core most things with 2-3 alphas. Inner Sphere does not have many laser boats and this one is quite reliable performer with the heavy armor, jump jets for mobility, and enough efficiency to run MPL loadout easily.
Edited by UrsusMorologus, 15 November 2014 - 11:40 AM.