"i was just wondering if the stepdown converter from the link would be alright for dropping 12v to 5v"
- well, er, um, if it works and is within your parameters then why not?
But is there a need for a swiching supply?
Switchers have far higher efficiency but produce noise. With a good design, both electrical and physical, can reduce the noise but you'll NEVER get rid of it. I've never used, or even heard of, the device you linked to. (Every man and his brother can make and sell on the nerdynet thse days). I could not tell you of it's quality.
Linear regulators are not so efficient but dead smooth.
If you gave a clue as to your application and current loads then people could advise. I have yet to design my swiched-mode crystal ball