Are some techs/wepons useless?

[pathfinder]

i have had to switch from phased polaron to anti-proton weapons against the Xi'Chung, simply because the later Version AP's did a BETTER job than the PP one's did. I also found out the hard way that the regular shields worked better aginst the Xi' Chung organic weapons (they like the electric gun) than do the pahsed shields.

I would research what works against an enemy or potential enemy, course you may have to find out the hard way what does or doesn't work