Encumbrance vs Armor Class tends to be dependent upon your character’s skills and which body parts you are encumbering.
For example, torso encumbrance lowers effective melee skills. If you have 5 torso encumbrance as a fresh character with no skills, you’re probably going to die when fighting melee. On the other hand, should you have your respective melee skill to your weapon as 10, 5 torso encumbrance from armor isn’t too bad, but isn’t ideal.
I would highly recommend going to the ‘@’ menu and finding out what each body part’s encumbrance does. If you’re not into ranged weaponry, you probably can wear some bindles without any detriment to your combat effectiveness, and so on.
In terms of Attack Speed vs Damage, I would be inclined to go for something that has a decent mixture of both and some special moves. Hit-bonus will be very handy at lower levels, and something like a rapier will probably do the trick nicely.
Heavy armor is probably most effective against bullets and brutes, but I personally like to travel light, with decent-enough armor (survivor gear, dragonskin vest, etc)
tl;dr - It’s not about what you’re wearing. It’s how you use it with your skills.