Since this is an old thread. And yes I'm still playing the game until now. Here are my side. Feel free to commend some stuff you wanted to say.
CM Gigavolt - MOST PROFOUNDED weapon of choice due to its speciality of jumping bolts of energy that can clear a whole swarm. Recommended to have atleast an adaptiveness or pinpoint on the side (depending if you are a medic or a assault class)
HIKS S300 - Good weapon that gives a high power damage and high dps thermal damage. General tip is go for adaptive and tenacious. But in nightmare mode due to the fact the bosses are quite buffed with resistances and this weapon is relatively not good in swarms or i mean in groups of zombies. If you want to find one. Get the RIA 50 though but not quite good in tough bosses specially with devastators and zombie mech (elite ones and nightmarish)
Lone Star - Best weapon on clearing out swarms of zombies. Preferrable with full augment of Deadly, OC , Race modded and skeletonized. Pretty much good on early stages. And if you are lucky to get a 10 grade. Well, good game. But not good on high levels due to the fact resistances quite occur very much
Poison Claw - Weapon specially best for starters. This weapon is more reliable in low levels than stripper due to its high tenacious damage and reliabilty. You can pick race modded and tenacious for this one.
Hornet - High powered, light, and fires fast than a car. Good for swarm clearing and boss battles. Pick an adaptive or pinpoint with some oc and deadly with race modded. Feel the charm with this weapon though. Its a paradise.
Mixmaster - High powered and highly capable of cleaning large quantities of swarmers. Pretty much doesnt need adaptive. Just pick pinpoint
Stripper - you know why this bad boi is good in high ranks.
And thats only a few. Theres a lot but thats my few recommendations. Keep it.