In order to find the best drill bits to drill in metal, you should look at the angle of the bit. It will need to have a center point. Bits only cut on the ends. The grooves on the sides are made to remove the excess. The point on the end determines how it will cut. Titanium bits last a long time, but cobalt bits last even longer. They will all eventually become blunt. They will require sharpening.
When you want to make a big hole in metal, you have to make a small hole first with a smaller bit. Then, you'll need to use increasing larger bit to make a larger hole. You can't start with a large bit.
Always wear safety goggles.