Yeah, unless there is a good reason to have a 12v source (such as an automotive application), go with native 5V.
Otherwise, you are putting a switching DC to DC converter to get down to 5ish volts or losing 7V x Current Draw of Project in power, for a linear 12v to 5v conversion. Neither are a great option. One can introduce a good bit of noise and the other a good bit of heat.
If you find some 6V adapters, you can poor man them down with some forward biased diodes dropping 0.6V a piece.