Those other tools often try to get a bit fancy allowing you to clone and resize at the same time. They often also go into the actual file system and copy file by file particularly if you are just imaging the disk - this allows them to ignore things like the pagefile, hibernation file etc. It probably makes them a lot fast with largely empty disks. Probably slower on a full disk though since there would be a lot of seeking instead of just raw reading straight off the disk.

I agree the cat (or dd) method would be the thing to try but it does rely on the new drive being bigger than the old one. Something this quote doesn't make exactly clear: