I've used all three types of scanners: drum, flatbed and hybrid (Imacon). For chromes, a drum scanner can't be beat. It's more versatile in every aspect of digitizing an image: productivity, ppi, dmax, gradation of tones, and a lower noise floor.
One downside: film mounting. It requires oils & cleaners & wipes. You'll need a mounting station if you want to scan dozens of images at a time.
They're also larger than every other type of scanner out there.Aztek
has great info on scanning.