Concerning the built-in Vac.

I have used both. There is no comparison in the suction between a good built-in and a portable. I use a 15 amp 230 volt built-in with centrifugal filtration and an outside vent. It roughs out vacuum bags in seconds. Also if you do anything that produces any toxic or semi-toxic vapor, it's very good to exhaust outside sometimes.

However, never use a built-in when grinding something that produces white sparks, don't ask.