I'm currently rerolling for the 3rd time. My current build being an 18 dex katana / mantis blade build. I don't recommend it at all. Katanas are good, and Mantis blades ups that being even better. However - only against single target. 90%+ of the encounters in this game, is facing bigger groups of armed enemies. Due to them zerging/flanking and how fast you die on Hard+, expect spamming heals and running for cover ALL THE TIME, and having to use ranged weapons despite not wanting to.
Want my advice for strong, solid and fun builds?
Body (main), Tech (secondary), reflex OR cool (tertiary) Shotgun build. Shotguns are extremely good both offensively and defensively due to knockdowns. Grenades also cause knockdown and synergizes strongly with engineering. Lots of HP+Armor+Movespeed. Tech shotgun benefits from both Engineering and the weapon skill itself. Kind of a double dipping. So grab a tech shotgun and go slaughtering.
Pistol + Anything. The pistol perks are the strongest in the game IMO. Seriously. If you go balls deep into pistols you can do all content fairly easy. Pistol perks are so strong in fact, that I'd say that even on Very Hard, your secondary investment don't matter.
Int (netrunner) + anything. Sucks early game. Extremely strong mid-lategame. If you have a lot of patience, and you know what you are doing, and willing to suck early game. This build really scales up later on. Not gonna go into details, but just gonna say that - the power scaling of a fully invested hacking character is immense. It just has a low curve early in the game.