Rob,

This is where your inexperience shows (But Good You Are Asking Questions), those router type machines use high speed spindles.

You need drilling on your part its very difficult to do drilling as you run out of Z axis clearance not to mention drilling at 8K rpm min

To take on bigger cuts in any material the machine must be built stronger than the material you are cutting and in IMHO those machines are too flimsy.

I have two mills one a manual Bridgeport that weighs about a ton and a benchtop that weighs 1/5 of a ton

Check out how much those router machines weigh, although you may get the job done the finish will be poor.

Just giving the facts so don't shoot the messenger.

Phil