Correct, a SDS drill generally can drill down with only it's own mass providing force. I find the Bosch SDS bits are the best in the cheap range, provided that you replace them when worn, though I have drilled holes with a bit that broke the tip off after hitting a granite stone chip. Light pressure is all you need, if the drill slows down pull the bit out to remove dust and carry on.
The common sizes I use are 6mm, 10mm, 12mmx300, 20mmx250 and a 65mm core bit. Generally the bigger sizes take longer, I often drill a 6mm hole so fast I have to be careful not to drill too deep.