ECM gives you cover for long range sniping, or riding with the big boys to provide ECM cover. ERPPC gives you range to snipe from a distance while being able to fight up close, and offers some serious pinpoint damage. 2 SRM6s give you the splat factor and often aim fairly well with the PPC. Also good for getting those exposed innards the PPC breaks open and swatting light mechs. For those that prefer the Artemis grouping, pull out 1 ton of ammo and swap to 2 cASRM4s I'm still fooling with it, but I think I've dropped in it once without at least one kill, and if you stick near the big boys, you augment their firepower with a fairly large (though spread) alpha up close, or some ranged firepower from afar. Obviously, this works on the Prime as well if you swap both arms rather than just the one.
After experimenting alot with the KFX, i find it to be the most effective build out there. Some long range punch, respectable alpha, easy to manage heat. I've switched 1/2 ton SRM ammo for a single jumpjet, but it's very effective even without JJ. 5/5
Looks good overall but I would down size the ERPPC to a ERLL and the SRM-6s to 4s to allow for AMS and 1-3 JJs. Just my .02 C-Bills.