Is higher weapon speed better, or lower

Weapons are all up to preference.

I've found that swing speed doesn't matter much as timing your attacks is more helpful than just spamming attacks.As for the spear vs. warhammer, the warhammer would be easier to hit with since it does an overhead swing, whereas the spear does a forward thrust.

Another thing to look at when comparing weapons is armor penetration, as that seems to be more important than straight damage.

Higher threat levels generally mean more abundant ores, and ores of higher rarity. However, especially rare ores like gold or diamond can still be hard to come by, generally occurring only at the deepest levels of the planet. Personally, I'm mining level 19 planets for gold and maybe producing 4 ores by the time I reach the planet's core. I found two gems (8 ores) worth of diamond in the 1-9 planets, and haven't seen any since.

That said, planet type may have something to do with it. I've noticed that moons contain a more ores than I'm used to, in addition to being a bit easier to dig through. Desert and arid planets are super easy sources of iron, copper and coal since you can just dig into the sand to dislodge everything.

Some advice: hoard your iron. You'll want it for Sector Beta.