Engraving aluminum and stainless (laser or carbide bit???)

I nned to do some engraving on stainless and aluminum. Some of the
parts will be round as well as flat. I would like to built/buy a CNC
engraver. Which would be best a laser or regular rotary cutter?
Does anyone have and good websites for help and building any of
these? I have a pretty good machine shop with some CNC capability.

Thanks

Scott