I've been using the DeWalt self-piloting "titanium" bits on old growth oak and steel with great success. They are a little aggressive on aluminum and very soft woods, unless you hold back on the drill they tend to spiral in. They cut through sheet steel very quickly. I've used several other brands but the DeWalt seem to deliver the best performance and durability for the price.

I have a box of steel drills and taps that were my grandfather's when he worked in tool and die. There are probably 1000 bits in the box including many carbide tips. The carbide tipped bits work well, but the steel bits dull quickly. Both are worthless on wood.

I don't resharpen bits except wood boring spades. They never seem as sharp as new, and the edge doesn't last long.

Just my observations and opinions...